Commentary Par XXXIII 127-132

Finally, Dante sees the Humanity of the Trinity, the Son, Jesus Christ, incarnate within the circle that abstractly represents the Second Person.  Once again the differing colors of the Persons are insisted on, and once again (see C.Par.XXXIII.118-120) Dante does not report the color of the Son (nor of the Father).

It took centuries before a commentator (Scartazzini [DDP Scartazzini.Par.XXXIII.131] realized that this image contained a reference to St. Paul (Philippians 2:7), 'but made himself nothing, taking the form of a servant, being born in the likeness of men.'  This is currently a fairly widespread perception, but the only other writer in the DDP to observe it is Grandgent (DDP Grandgent.Par.XXXIII.131).  The enormous presence of the Bible in the poem has at times simply overwhelmed its observers.  This is a case in point.  Moore (Moor.1896.1), pp. 321-34, lists over six hundred possible citations in all Dante's works, the bulk of them in the Commedia.  Thus one needs to deal cautiously with Steiner's accountancy (Stei.2001.1), p. 89, which counts the actual citations (rather than more general forms of reference) as two in Inferno, eight in Purgatorio, and a dozen in Paradiso.

See also Dronke (Dron.1975.2), pp. 7-8, arguing that this, too (see [Par XIV 67-78] and C.Par.XIV.67-78) is a reference to Joachim's three Ages, represented by three circles in the Liber figurarum.