Commentary Purg XXVII 58

As, among the early commentators, only he who speaks from the pages of the Codice Cassinese pointed out, the passage reflects the words that Christ will speak to the just at the Day of Judgment: 'Then shall the King say unto them on his right hand, "Come, blessèd of my Father, take possession of the kingdom prepared for you from the [time of the] foundation of the world'" (Matthew 25:34).  In the twentieth century, notice began again to be paid to this absolutely relevant text.  As Singleton reports (DDP Singleton.Purg.XXVII.58), Wilkins (Wilk.1927.1), p. 5, pointed out that a mosaic in the Florentine Baptistery showed a gate guarded by an angel who welcomes a newly arrived soul, while a second angel leads a group of the saved and carries a banner that is inscribed 'Come, blessèd of my Father, possess what has been prepared.'  Dante's second and singing angel would certainly seem to be modeled on that second angel and his words.  And that there are two angels on this terrace may reflect his memory of the mosaic.