- the theology of Hell is first presented here, albeit in highly condensed and unexplicated form: the opening of Inferno 3 introduces us to justice — “Giustizia mosse il mio alto fattore” (Justice moved my high Maker [Inf. 3.4]) — and its implied correlative, free will
- Hell is a non-deterministic and freely chosen state, as enacted in verses 124-126
- Dante generates tension throughout Hell by means of the dynamic interplay between the reader’s feelings of sympathy for the damned and the reader’s intellectual awareness (not yet fully informed) of the concept of justice
- the concept of eternity and the asymmetry of Hell and Paradise; disregard the instruction manuals on the Commedia that indicate that Hell and Paradise are opposite but symmetrical in being eternal
- the eternity of Hell is of a different order from the eternity of Paradise: eternity of Hell signifies duration, while eternity of Paradise signifies an eternal present
- while Dante embraces high theology with respect to justice, free will, and eternity, he turns to more popular and less theological traditions in creating a space for the so-called “neutral” angels and for the souls of those who were somehow not evil enough to be received into Hell
- Inferno 3 depicts a protracted limen (threshold): a liminal space before we reach Hell itself, a space that represents the pivot point of choice between the two binary realities of this universe: damnation or salvation
- this space, the ground of transition itself, is not named by Dante; in the commentary tradition it is frequently called Ante-Hell or vestibule of Hell
- the first contrapasso: here again we encounter Dante’s disdain for moral neutrality (as discussed by Martin Luther King, Jr.), his commitment to commitment
- the case of the moral failure of Pope Celestine V, and the challenge issued to him by one Franciscan poet, Jacopone da Todi
- the ongoing story-line of the pilgrim and his guide: the “first tiff” between Dante and Virgilio
 This canto is liminal. It is about crossings: whether passing through the gate of Hell or passing over the River Acheron. It therefore begins with the gate of Hell: the limen (threshold) of Hell that the pilgrim must pass through in order to enter the dark realm. It contains first things: the first description of Hell, the first group of souls in Hell, the first punishment and the first opportunity for the reader to consider the formula by which punishments are allocated (a principle that Dante will call, in Inferno 28.142, the “contrapasso”), the first infernal guardian (the boatman Charon who ferries Dante across the river), and the first opportunity to consider the way that the infernal guardians treat Dante.
 It will turn out at canto’s end that, once past the Gate of Hell, we have not yet fully entered Hell itself; to enter Hell we must cross the river Acheron. In this way Inferno 3 dramatizes the idea of transition and the increments by which a soul arrives at the ultimate crossroads: the choice of sin.
 Most important of these firsts, perhaps, is the first appearance of the word “justice”: “Giustizia mosse il mio alto fattore” (Justice moved my high maker [Inf. 3.4]). These words are conspicuously written on the gate of Hell itself, issuing a challenge that we likely do not fully perceive upon first reading the Commedia. While on the one hand the sinners’ life-stories, as vividly dramatized in the poetry of the Commedia, are frequently such as to elicit compassion from the reader, compassion is an inappropriate response if the sinner is in fact, as the gate declares, justly punished.
 From a theological perspective, the concept of justice implies the concept of free will. If there were no free will, the allotment of Hell or Paradise would be deterministic rather than the result of giustizia.
 The idea that Hell is an arbitrary assignation rather than the consequence of one’s own choices is a theologically unacceptable proposition, as Marco Lombardo explains to the pilgrim in Purgatorio 16.67-72. For the question of determinism, much debated in Dante’s time, see also the Appendix on Cecco d’Ascoli (who accused Dante of determinism) in the Introduction to Inferno 7. For the rebuttal of the deterministic position, see the Introduction to Purgatorio 16.
 From a narrative perspective, the word giustizia in verse 4 therefore initiates the conflictual process that is at the core of Dante’s artistry in Inferno: the conflict generated by the tension between the “justice” that governs the placement of souls in Hell and the pity for the damned that the poet skillfully conjures from his readers.
 On the one hand Dante will tell us that Hell is the place “where pity lives when it is truly dead”: “qui vive la pietà quand’è ben morta” (Inf. 20.28). On the other, the poetic pathos that Dante scripts for some (by no means all) of the sinners in his Hell has led to generations of readers who sympathize with many the characters in Inferno. Sympathy leads to identification, and stimulates thought in the reader about the sometimes mysterious nature of sin and its outcomes. In this way Dante, the poet, creates dramatic tension in a narrative that is otherwise — but for his extraordinary poetic power — completely overdetermined.
 There are words engraved on the gate of Hell (they are written, “scritte” in verse 11): they are written by Someone, in terza rima. There are striking rhetorical features: for instance the anaphora of the first three verses (anaphora is the repetition of words at the beginning of two or more successive verses, in this case the ominously repeated “per me si va”: “through me the way”). Also noteworthy is the word that is repeated most often throughout the inscription, namely the adjective “eternal” in various forms. This gate, we are told, will endure eternally: “e io etterno duro” (and I endure eternally [Inf. 3.8]). The message here regarding the eternity of Hell is a theological one — and it is forbidding.
 The eternity of Hell was debated by early theologians before being “settled” by St. Augustine. Origen affirmed the medicinal and corrective value of a non-eternal system of punishment that would eventually restore all souls to God. However, Augustine vigorously and successfully defended the eternity of Hell, using Matthew 25 and arguing as follows:
the sentence of the Lord could not be evacuated of meaning or deprived of its force; the sentence, I mean, that he, on his own prediction, was to pronounce in these words: “Out of my sight, accursed ones, into the eternal fire which is prepared for the Devil and his angels’’ (Augustine, City of God, trans. Henry Bettenson [London: Penguin, 1972], pp. 21–23)
 I discuss the importance of Augustine in the context of the theology of Hell in “Medieval Multiculturalism and Dante’s Theology of Hell”, cited in Coordinated Readings. It is also worth noting that the eternity of Hell is still debated by some Christians today: see http://rethinkinghell.com/.
 The symmetry of Hell and Paradise as eternal realms, much posited by Dante commentaries, is not in fact accurate. As I clarify in The Undivine Comedy, the eternity of Hell is of a different order from the eternity of Paradise. The eternity of Hell is “sanza tempo” — “without time” (Inf. 3.29), as we learn in this canto. The eternity of Paradise, on the other hand, is “di tempo fore”: “outside of time” (Par. 20.16).
 Eternity of Hell signifies duration, while eternity of Paradise signifies an eternal present:
Hell is defined as eternal, but in his representation of hell Dante never problematizes the concepts of space and time as he does in his representation of paradise; he never says (the very ludicrousness of the proposition is telling) that all the souls are really with Lucifer in Cocytus and only appear in various circles for the benefit of the pilgrim. Spatially, hell is treated as tangible and concrete, while temporally, the fact that it is eternal means only that it will last forever, that its torments are perpetual.
Eternity in the context of hell signifies duration; as Aquinas notes, “The fire of hell is called eternal only because it is unending” (ST 1a.10.3; Blackfriars 1964, 2:143). In conceptualizing paradise, on the other hand, Dante moves from an interminable duration to an eternal present, to that which is outside of time altogether: the divine mind exists “in sua etternità di tempo fore” (in his eternity outside of time [Par. 29.16]). Dante seems to have applied to his two realms Boethius’s distinction between perpetual endlessness and eternal timelessness: the air of hell is “without time”—“sanza tempo” (Inf. 3.29)—because it is starless and therefore endless, deprived of the measured time produced by the motion of the spheres, not because it is truly timeless and eternal, altogether outside of time, “in sua etternità di tempo fore”. (The Undivine Comedy, p. 170)
 In Inferno 3 the voyagers traverse the gate of Hell at the beginning, and the river Acheron at the end. The canto is essentially a protracted limen, a protracted threshold, entrance-hall, or portal. Dante here further dramatizes the idea of liminality by conjuring a group liminal souls who inhabit this space: souls who are received neither by Heaven nor by Hell. Dante here conjoins two popular (rather than theological) traditions: that of the so-called “neutral” angels and that of souls who are neither good nor bad.
 The souls the travelers see here do not belong to the first circle of Hell, which we come to only in Inferno 4. Rather the souls featured in Inferno 3 are themselves liminal, like the space they inhabit. They are the souls of people “who lived without disgrace and without praise”: “che visser sanza ’nfamia e sanza lodo” (Inf. 3.36). These are the souls of the morally neutral. In classical terms, these are the “pusillanimous”, the opposite of the “great-souled” or “magnanimous”.
 The souls of humans who committed themselves neither to good nor to evil are commingled here with the wicked angels who neither were faithful to God nor rebelled against Him but were “for themselves”: “quel cattivo coro / de li angeli che non furon ribelli / né fur fedeli a Dio, ma per sé fuoro” (the wicked angels, the company of those who were not rebels nor faithful to their God, but for themselves [Inf. 3.37-9]).
 The rebellious angels were cast from the heavens and became devils. They are those to whom Dante refers as “da ciel piovuti” (rained down from heaven [Inf. 8.83]) and “cacciati del ciel” (cast from heaven [Inf. 9,91]). In contrast, the “wicked chorus” (“cattivo coro”) of angels who were “for themselves” (“per sé fuoro”) were cast from heaven but not received into “deep hell”: “Caccianli i ciel per non esser men belli, / né lo profondo inferno li riceve” (The heavens, that their beauty not be lessened, / have cast them out, nor will deep Hell receive them [Inf. 3.40-41]). Rather, they remain for eternity in this liminal space.
 Dante here imagines a group of souls, and mixed with the souls a group of angels, whose vice is that they did not commit. These souls are “hateful to God” and simultaneously they are hateful to “His enemies”: “a Dio spiacenti e a’ nemici sui” (Inf. 3.63).
 In elaborating this category Dante invokes repeated binaries, as in “hateful to God and to God’s enemies” (Inf. 3.63), and he then constructs a spectrum whereby the vice of these souls is to be in the middle: neither received by God in Paradise nor received by God’s enemies in Hell. Perhaps inspired by the Aristotelian scheme that places vice at either end of a spectrum and virtue in the middle, Dante here creates a unique scheme of his own. He starts with the idea of virtue that is opposed to vice: for instance, the faithful angels versus the rebel angels belong to a binary typical of the Christian imaginary, which conceptualizes virtue in opposition to vice. He then grafts onto the Christian binary the idea of a spectrum (imported from Aristotle), in order to arrive at the idea of a vicious condition that is middling: in between virtue and vice.
 But, at the same time, Dante does not really conceptualize these souls and these angels as morally in-between. They are the “cattivo coro” (37), they are the “la setta d’i cattivi” (62), where the term cattivo does not just signify cowardice but also slants toward wickedness. After all, the so-called “neutral” angels are not geographically neutral or geographically in-between; they are not equidistant between Heaven and Hell. Rather, Dante locates them on the very threshold of Hell.
 Dante has created a space that represents the pivot point of choice. As I write in The Undivine Comedy, this space is transition itself:
The place in canto 3 is transition incarnate. Its identity is conferred by what it is between: it is between the gate of hell and the river Acheron, which the pilgrim will cross at canto’s end. To reach that crossing, that point of commitment, that Rubicon at which transition is ratified, the pilgrim must transit the place of transitions in canto 3. It is also a place that tells us a great deal about the character and methods of our poet. Morally, this place serves as an index of engagement, dramatizing his commitment to commitment by creating a category for those who rejected both good and evil (but who are, we note, by no means positioned equally between the two). (The Undivine Comedy, p. 32)
 This vestibule of Hell dramatizes Dante’s commitment to commitment. Dante here shows his willingness to manipulate the theology of Hell in order to express his profound disdain and aversion to a state of ignominious and pusillanimous non-commitment.
 The idea of souls who are not “evil enough” to be received into Hell is a remarkable one that has gained much traction over time. Martin Luther King captures the essence of Dante’s point in his speech “Why I Am Opposed to the War in Vietnam” (April 30, 1967):
Now, I’ve chosen to preach about the war in Vietnam because I agree with Dante, that the hottest places in hell are reserved for those who in a period of moral crisis maintain their neutrality. There comes a time when silence becomes betrayal.
 King does not get the technical part right: Dante does not place these souls in “the hottest places in hell” because — and this is the grandeur of Dante’s idea — his point is that they are so base that they are not even admitted to Hell. But King captures completely the key idea of moral neutrality as betrayal: “There comes a time when silence becomes betrayal”.
 Non-commitment that is tantamount to betrayal is represented in Inferno 3 by one soul in particular. The travelers pass by the shade of the man “who made, through cowardice, the great refusal”: “colui / che fece per viltade il gran rifiuto” (Inf. 3.59-60).
 Importantly, Dante stipulates that he recognizes this soul. Moreover, Dante so stipulates with incontrovertible clarity: “vidi e conobbi l’ombra di colui / che fece per viltade il gran rifiuto” (I saw and recognized the shade of him / who made, through cowardice, the great refusal [Inf. 3.59-60]).
 However, Dante does not give us the soul’s name. We can therefore surmise his view: the fitting consequence of moral cowardice is erasure from the rolls of both Heaven and Hell.
 The souls in this vestibule of Hell have been sent here for eternity. As we shall see, they run after a banner, an activity that symbolizes their failure to follow any cause — any banner — while alive. As poet and recorder of souls in the afterlife, Dante has moreover devised a punishment within the punishment. The primary punishment is being sent for eternity to this vestibule of Hell and chasing a meaningless banner. As a punishment within this punishment Dante has devised the idea of non-recognition.
 The deprivation of recognition in this vestibule takes on more significance when we consider that a major feature of Dante’s Inferno is the craving of the souls whom Dante meets for recognition. All the way to the very bottom of Hell, the souls desire to have their stories told by Dante when he returns to earth, seeking a kind of immortality through his narrative.
 The consensus of scholars is that “colui che fece per viltà il gran rifiuto” is Pope Celestine V, but the verse necessarily remains controversial. To start with, as explained above, Dante has devised a contrapasso that includes anonymity. As Virgilio instructs Dante: “non ragioniam di lor, ma guarda e passa” (let us not talk of them, but look and pass on [Inf. 3.51]). Further, although most 14th century commentators concurred in believing that the verse refers to Celestine, the canonization of Celestine V in 1313 added to the challenges of the interpretation. There were those who have argued that Dante would not so treat a canonized saint. I have never found the latter argument persuasive.
 Celestine V (1215-1296), whose secular name was Pietro di Morrone, was pope for five months in 1294. He was elected pope 5 July 1294 and abdicated 13 December 1294. He became a Benedictine at age 17 and was a pious and solitary hermit:
His love of solitude led him first into the wilderness of Monte Morone in the Abruzzi, whence his surname, and later into the wilder recesses of Mt. Majella. He took for his model the Baptist. His hair-cloth was roughened with knots; a chain of iron encompassed his emaciated frame; he fasted every day except Sunday; each year he kept four Lents, passing three of them on bread and water; the entire day and a great part of the night he consecrated to prayer and labour. (Catholic Encyclopedia, http://www.newadvent.org/cathen/03479b.htm)
 The Catholic Encyclopedia recounts the scene that led to Pietro di Morrone becoming pope, declaring it “unparalleled in ecclesiastical history”:
Three eminent dignitaries, accompanied by an immense multitude of monks and laymen, ascended the mountain, announced that Pietro had been chosen pope by unanimous vote of the Sacred College and humbly begged him to accept the honour. Two years and three months had elapsed since the death of Nicholas IV (4 Apr., 1292) without much prospect that the conclave at Perugia would unite upon a candidate. Of the twelve Cardinals who composed the Sacred College six were Romans, four Italians and two French. The factious spirit of Guelph and Ghibelline, which was then epidemic in Italy, divided the conclave, as well as the city of Rome, into two hostile parties of the Orsini and the Colonna, neither of which could outvote the other. A personal visit to Perugia, in the spring of 1294, of Charles II of Naples, who needed the papal authority in order to regain Sicily, only exasperated the affair, hot words being exchanged betrween the Angevin monarch and Cardinal Gaetani, at that time the intellectual leader of the Colonna, later, as Pope Boniface VIII, their bitter enemy. When the situation seemed hopeless, Cardinal Latino Orsini admonished the fathers that God had revealed to a saintly hermit that if the cardinals did not perform their duty within four months, He would visit the Church with severe chastisement. All knew that he referred to Pietro di Murrone. The proposition was seized upon by the exhausted conclave and the election was made unanimous. Pietro heard of his elevation with tears; but, after a brief prayer, obeyed what seemed the clear voice of God, commanding him to sacrifice his personal inclination on the altar of the public welfare. Flight was impossible, even if he contemplated it; for no sooner did the news of this extraordinary event spread abroad than multitudes (numbered at 200,000) flocked about him. (Catholic Encyclopedia, http://www.newadvent.org/cathen/03479b.htm)
 Although Celestine V was not a Franciscan, he was viewed with great favor by the extreme wing of the Franciscan order known as spirituals, who advocated literal observance of Francis’ Rule: “His elevation was particularly welcome to the Spirituals, who saw in it the realization of current prophecies that the reign of the Holy Spirit ruling through the monks was at hand; and they proclaimed him the first legitimate pope since Constantine’s donation of wealth and worldly power to ‘the first rich father’ (Inferno, Canto XIX)”. (Catholic Encyclopedia, http://www.newadvent.org/cathen/03479b.htm)
 As we can see, there were great expectations of Celestine V when he became pope. One Franciscan, the poet Jacopone da Todi (1236-1306), expresses these expectations in his poem, Que farai, Pier da Morrone?. Here Jacopone da Todi challenges Pietro da Morrone to reform the Church:
Que farai, Pier da Morrone? Èi venuto al paragone . . . Guàrdate da baratteri, ch’el ner per bianco ’l fo vedere; se non te ’n sai bene scrimire, cantarai mala canzone. (Jacopone da Todi, Que farai, Pier da Morrone?)
What will you do, Pier da Morrone? You have come to the moment of truth . . . Look out for barattieri who make you see black for white; if you do not know how to distinguish yourself clearly from them, you will sing a sad song.
 The figure of Pope Celestine V and the issue of his abdication were thus very complicated and controversial for contemporaries who were committed to reforming ecclesiastical corruption.
 Dante shared many of Celestine’s views. Dante leaned toward the asceticism of the Franciscan spirituals and founded his politics on the principle that the church was corrupted by the Donation of Constantine and should have remained in its state of initial purity and poverty. Dante expresses these views throughout the Commedia, offering a first huge installment of his position in Inferno 19, the canto in which he explicitly condemns to Hell corrupt popes and fellow clergy. (Hence the reference to Inferno 19 in the above citation from the Catholic Encyclopedia’s entry on Celestine V.)
 Many of Celestine’s positions regarding poverty and humility would have been deeply congenial to Dante. But, on the other hand, Celestine’s congenial views only make the consequences of his abdication harder to bear. For Dante, Celestine’s abdication of the papacy is an object lesson in the devastating consequences wrought by lack of commitment, by insufficient moral courage, for his abdication allowed Boniface VIII to become pope. On balance therefore I find the arguments identifying “colui che fece per viltà il gran rifiuto” with Celestine quite compelling.
 That said, we must remember that the text deliberately “refuses” to record the name of “colui / che fece per viltade il gran rifiuto” (Inf. 3.59-60). As we saw above, the narrator is crystal-clear about Dante’s recognition of the soul (“vidi e conobbi” [Inf. 3.59]), thus indicating that he could have identified him if he had chosen to do so. In other words, the name is deliberately withheld and erased.
 We will never know with certainty the identity of this great exemplar of moral cowardice.
 Our readerly discomfort with our lack of total certainty as to the identity of “colui / che fece per viltade il gran rifiuto” is an experiential analogue to the ambivalence that consigned the unidentified soul to this ambivalent space in the first place. In this way Dante devises a narrative strategy that makes us in some way participants in the uncertainty and ambivalence that haunt this space: this limen invented by Dante for his Hell.
 It is worth remembering that the “viltade” of this unnamed soul echoes the pilgrim’s own state in the previous canto, where Virgilio remarks that “l’anima tua è da viltade offesa” (your soul has been assailed by cowardice [Inf. 2.45]). In other words, Dante has just dramatized his own hesitation to accept the arduous responsibility that has been assigned to him. Supported by Beatrice and Virgilio, however, he was able to find the moral courage to soldier on: “a sostener la guerra / sì del cammino e sì de la pietate” (to undergo the battle / both of the journeying and of the pity [Inf. 2.4-5]).
 The shades of “Questi sciaurati, che mai non fur vivi” (These wretched ones, who never were alive [Inf. 3.64]) run behind a banner and are stung by horseflies and wasps. The afterlife enforces upon them, by a perverse discipline, the commitment that while they were alive they never embraced: they race after a banner in an infernal (per)version of embracing a cause. Now they are perforce committed, but they are committed to nothing of any value.
 We can consider the behavior of these souls to model the first contrapasso of the Commedia. These souls’ futile chasing after a banner while being viciously stung is our first encounter with the application of the rule, common to vision literature, whereby (as Gilbert and Sullivan memorably put it) the punishment fits the crime. For Dante’s only use of the word contrapasso, see the Introduction to Inferno 28.
 Dante’s methodology in constructing his contrapasso is to literalize metaphors: Hell is the place where the metaphor that applies to your sinful inclination is turned into literal (and eternal) reality. In the case of the “These wretched ones, who never were alive“ the contrapasso works by contrariness: the souls now perform what they did not do in life, its contrary. Most often, in Inferno, Dante will apply contrapasso by analogy: thus, for instance, the lustful souls are buffeted by an infernal windstorm that is analogous to the passions that they permitted to buffet them during their lives on earth.
* * *
 The second half of Inferno 3 is devoted to the crossing of the river Acheron; as in many myths and much history (for instance, Caesar’s crossing of the Rubicon), the crossing of the river marks the completion of the transition and the arrival into a new state.
 The classical ferryman Charon, imported from Book 6 of the Aeneid and then infernally revised, like many of the mythical guardians of Inferno, ferries the souls across the river. When Dante himself tries to get into Charon’s boat, he is rebuffed, instructed that a “a lighter craft will have to carry you”: “più lieve legno convien che ti porti” (Inf. 3.93). From this passage we can glean important information about the construction of the Commedia.
 From Inferno 1.114-20 we know that Dante had broadly conceptualized his project as embracing the three realms of the afterworld. From the ”lighter craft” that will take him to shore by “another way and other harbors” — “Per altra via, per altri porti / verrai a piaggia” (Inf. 3.91-2) — we learn more: Dante knows that his Purgatory is on the water and that its shores are reached by boat.
 The viewing and discussion of the “wretched ones, who never were alive” ends at verse 69. At this point the pilgrim devotes himself to “looking beyond”; now he sees souls massed on the bank of a great river: “E poi ch’a riguardar oltre mi diedi, / vidi genti a la riva d’un gran fiume” (And then, looking beyond them, I could see / a crowd along the bank of a great river [Inf. 3.70-71]).
 The pilgrim immediately discerns in the souls on the riverbank a marked desire to cross the river, “trapassar“ (74), and he formulates two precise questions for his guide. He wants to know who the souls are and what “costume” (law or usage) makes them so “pronte” — so “ready” — to cross (“trapassar”): “qual costume / le fa di trapassar parer sì pronte” (what law / has made them seem so eager for the crossing [Inf. 3.73-4]).
 The latter question about the mechanism that prompts the souls to desire to cross the river is noteworthy, in part because it will serve in narrative terms to create the opportunity for the narrator to create the “first tiff” between the pilgrim and his guide. Virgilio does not answer, but tells Dante, with some severity, that these matters will become known to him further on, when they reach the riverbank. The pilgrim falls silent, ashamed, fearing that his pushy questioning has offended his guide: “Allor con li occhi vergognosi e bassi, / temendo no ’l mio dir li fosse grave” (At that, with eyes ashamed, downcast, and fearing / that what I said had given him offense [Inf. 3.79-80]).
 In Dante‘s Poets I outline the narratological principles that Dante devises for his Dante-Virgilio story-line, showing in chapter 3 how moments of intellective stress — for instance, when Virgilio does not know the answer to a question despite being the greatest of sages — are compensated by increased affective connection between the two travelers. With respect to Inferno 3, I note that “the first tiff between the pilgrim and his guide (Inf. Ill, 76-81) is followed by Vergil’s first ‘Figliuol mio’ (Inf. Ill, 121)” (Dante‘s Poets, p. 244, note 56).
 But what was it that annoyed Virgilio? Perhaps, we might speculate, we are here facing a Christian mystery that Virgilio does not really know how to explain. Or maybe this question is awkward for him to think about because he himself dwells on the other side of the river Acheron, in the first circle of Hell. By implication, according to the terms of this possible world that Dante is creating, Virgilio himself once felt a similar damning desire to cross the river.
 While no full explanation is given, Virgilio does add important information in his final affirmation of the costume whereby the damned souls desire to cross the river. Picking up, rather kindly, the precise words that Dante had used in his query as formulated in verses 73-4, Virgilio in verse 124 returns to the issue of how “ready” (“pronti“) the souls are to “cross” (“trapassar“).
 Virgilio now adds, looping back to the words on the gate of Hell at the beginning of Inferno 3, that it is “divina giustizia” (divine justice) that spurs the souls, causing their fear to convert into desire:
e pronti sono a trapassar lo rio, ché la divina giustizia li sprona, sì che la tema si volve in disio. (Inf. 3.124-26)
and they are eager for the river crossing because celestial justice spurs them on, so that their fear is turned into desire.
 Included within the purview of justice is therefore a mechanism that causes sinners to desire their eternal torment, that converts their fear into desire (Inf. 3.126).
 The mysterious “disio” of verse 126 seems to allude to the unspoken doctrine that undergirds the concept of divina giustizia: namely, the doctrine of free will. According to the theology of Hell as a non-deterministic and freely chosen state, these souls actively embraced evil while they were alive. Hence the disio that they express on the shores of Acheron.