Commentary Purg XXXI 2-3

The metaphor of Beatrice's speech as a 'sword' picks up her earlier promise that Dante will weep for 'another sword' beside that of Virgil's departure ([Purg XXX 57]).  The lengthy speech that she had directed to the angels ([Purg XXX 103-145]) was in fact aimed squarely at him, using the angels as her apparent primary auditors in such a way as to publicize his sins and thus shame the protagonist.  In this sense, then, the point of her 'sword' had seemed aimed at them, wounding Dante (if painfully enough, as we have seen) with the edge of the blade.  Now he finds her sword pointing straight at his heart.

      Chimenz (DDP Chimenz.Purg.XXXI.16-18) is perhaps the only commentator to fret over these angels; he cannot understand how they at first remained hidden from Dante and how so many of them could occupy so small a chariot (an unconscious resuscitation of the angels-on-the-head-of-a-pin problem or, perhaps, of the crowded condition of that stateroom in the Marx Brothers' A Night at the Opera).  Most commentators quite naturally assume that they descended from the Empyrean.  (None does so more clearly than Singleton, who is at least clear in voicing this opinion [DDP Singleton.Purg.XXXI.13-18].)  We, however, are not told this.  Further, their eventual removal from the scene is never dealt with, at least not directly (see C.Purg.XXXI.77-78).  All we can say is that they either mount up with the rest of the Church Triumphant ([Purg XXXII 89-90]) or, since their coming was so mysterious, that they simply vanish.  Either of two answers would, therefore, on the basis of the evidence in the poem, be consistent.