"O frati miei, Dio vi dea pace."
Noi ci volgemmo sùbiti, eVirgilio
rendéli 'l cenno ch'a ciò si conface.

 Commentators from Lana to the present have puzzled over what Virgil might have said or done here. Lana leads a long parade of scholars towards grammatical perdition when he suggests that Virgil's 'cenno' was the phrase "et cum spiritu tuo" -- a response that, while certainly common, provides neither a gesture, nor even an object for the verb 'dea.'

 In the past two centuries, a consensus gathered around the notion, advanced by Vandelli and Grandgent, that "cenno" must refer to a physical gesture. Singleton more or less put the issue to rest when he wrote, "It is surely a gesture (a bow or sign with the hand) and not a verbal reply, for this Virgil then gives." Indeed, not only does Dante not hide the verbal response under the guise of a gesture, he doesn't hide it at all. Virgil does respond, in his own fashion, after giving the appropriate gesture. So the poem tells us.

 But if this solution is so obvious, why did it take so long to reach it? Most probably because the terzina seems to cry out for a formulaic verbal finish. After all, it is difficult to think of a well-known custom in which a verbal formula invites a particular physical reply. On the other hand, as Longfellow notes, "among the monks of the Middle Ages there were certain salutations, which had their customary replies or countersigns. Thus one would say, "Peace be with thee!" and the answer would be, "And with thy spirit!" Or, "Praised be the Lord!" and the answer, "World without end!" Despite the fact that he has no useful suggestion as to what the verbal formula might be, Longfellow does get at the meat of the problem: the salutation sounds as though it wants a verbal finish, but all we're given is a gesture. Whether the literal sense of "cenno" is abused or not-amid all of the "et cum" and head nods (Benvenuto) and kisses of peace (Heilbronn) and "pacem et gaudium" (Serravalle) and signs of thanks (Bianchi) -- not a single satisfactory answer has emerged.

 In examining the topic, one might eventually conclude that Dante did not befuddle seven centuries of commentators by accident; but rather, that he knew what he was doing. He knew that 'Dio vi dea pace' would suggest a verbal response, because there was a perfectly suitable phrase in common usage. But he intentionally writes "cenno" for two reasons: (a) there is, indeed, a companion gesture to the intended phrase, and (b) by giving us only the gesture, he makes us feel the absence of that intended phrase all the more acutely. While "cenno" can only describe a physical gesture, we must first hit upon the intended verbal response before we can understand what the gesture had to have been-and why Virgil has to make it in silence. This silence -- and then his subsequent reformulation of the intended response -- lends significance and poignancy to the poem and to Purgatorio XXI in particular.

 The canto is primarily concerned with one issue: the revelation of eternal life. Dante opens by comparing himself to the Samaritan woman at the well -- the one who seeks water but who, Jesus reveals, is really thirsting for eternal life. Dante's thirst is redirected by Statius, who explains to him the meaning of the earthquake; namely, a soul's entering eternal life. But Statius is also Christ in a second Biblical analogy: that of the grieving disciples on the way to Emmaus. In the gospel, Jesus comes to these disciples and explains Old Testament prophecies as prefigurations of Jesus Himself as the Christ and of His resurrection. In these two stories, Jesus is the ultimate exegete-in the first, of an individual's own story of salvation, and in the second, of the universal story of salvation. Statius does the same, first by slaking Dante's personal "thirst" and then, by explaining how Virgil's writings contained the story of salvation.

 The dichotomy introduced here -- personal salvation and universal salvation -- is at the heart of Christendom's pre-apocalypse anxiety. Though the universe has been redeemed, each soul hangs in the balance of its own decision to accept or reject grace. By putting himself in the role of the Samaritan woman and the grieving disciple, he is both a sinner being redeemed, and the seer of a prophetic vision of eternal life. As a poet, he binds the two together. Like Virgil, he writes a poem that is, in a sense, scriptural; unlike Virgil, he uses this scripture to announce his own salvation. Virgil can announce salvation for all (or at least for Statius), but not for himself. And if asked to do so, he would, in justice, have to remain silent. As we will see, this is precisely what happens in line fifteen of the canto.

 In Dante's time the phrase "Dio vi dea pace" might have called many sources to mind beyond the greeting of Christ on the road to Emmaus. The Franciscan order used the greeting "Dominus det tibi pacem," which St. Francis claimed to have received from God. But probably the most familiar source of this expression would be found in the priestly breviary and in the Liturgy of the Hours -- prayers said by Christians to punctuate the hours of the day. The Hours were perhaps the second most common form of prayer (after the Mass) in Dante's time. It is common for these prayers to end with the versicle "V. Dominus det nobis suam pacem. R. Et vitam aeternam." This expression worked itself in other prayers of religious orders, most notably a common prayer of thanksgiving after meals, in the form "V. Deus det nobis pacem. R. Et vitam aeternam."

 Campi, writing at the end of the last century, mentions this verse in his commentary: "E tutta la terzina viene a dire lo stesso che la preghiera della Chiesa: 'Dominus det nobis suam pacem et vitam aeternam.'" However, he must not have seen it in the Liturgy of the Hours, because he would have noted two things: first, the verse/response format; and second, the visual rubric, represented by a cross in the midst of the text, which instructs a congregant to make the sign of the cross.

V. Dominus † det nobis suam pacem.
R. Et vitam æternam. Amen.

 Four decades later, Steiner, without noting this prayer, makes an important point about Dante's elision: "A Virgilio non si fanno mai pronunciare formule sacre ne compiere atti rituali." Among the sacred expressions forbidden to Virgil, those containing the phrase "vitam aeternam" must be at the top of the list. And if there is a border between what is permitted to Virgil and what is not, it falls precisely between "pacem" and "vitam aeternam." The divine will cannot allow Virgil to petition for anything beyond that "pacem" which he enjoys -- however imperfectly -- in limbo. God can't allow it, Virgil can't say it, Dante can't write it-not just because it is impossible, but because it would be unjust. While men may run amok in this world, there can be no injustice in the next.

 But there is no reason why Virgil can't make the gesture. He is not only capable of piety; he is an exemplar. Indeed, Dante does not edit Virgil, but rather, by recording Virgil's proper silence -- his devout "cenno" in place of words -- he highlights the teacher's pre-covenant righteousness. Virgil can't announce his own salvation, which does not exist, but he can give witness to the general salvation, as Statius testifies. And when he does finally speak, he does so with the utmost rectitude and charity.

"Nel beato concilio
ti ponga in pace la verace corte
che me rilega ne l'etterno essilio"

 As Benvenuto writes, "Virgilius captat benevolentiam optando illi illud bonum quod pro se numquam sperat." This unfulfilled righteousness is at the heart of Virgil's poignancy. He points toward what he cannot himself see. In this world and in the next, Virgil gestures at faith, but does not profess it.

 Thus, 'cenno' may well be the sign of the cross-the site of our universal victory over death. But the sign is perhaps less important than the absence of the words "vitam aeternam." The "cenno" is the silence of Virgil when asked to wish for his own salvation, and the silence of Dante when, as poet, he is asked to explain his guide's damnation -- a silence akin to Job's resignation before God's perfect and incomprehensible justice. The fact that Dante shows the very words of salvation extinguished in the mouth of his poet, his guide, his teacher, must give credence to those who believe that, far from imagining the afterworld as a mere poet's whim, Dante stands as the seer and scribe of an ecstatic and terrible vision.