The Creator compares himself to the lowest of his creatures so that you may regard nothing as despicable which is known to have been fashioned by his agency. As Scripture has it, “God made all things very good.” Thus David too followed his Teacher and compared himself with the humblest flea; for the real power of religion is that the more an individual humbles himself after the model of the Creator, the more splendidly he is exalted to glory.
Whom do you persecute, king of Israel? Whom do you persecute? etc. Israel means a man seeing God. Whom then do you persecute, O people, who were chosen before all other nations to see the glory of divine brightness? Whom do you persecute? Is it that great and most vigilant shepherd of holy sheep, whom you did not hesitate to betray to death and continue to hate even after his death? He who was lowly in human appearance but swift in the leap of resurrection, having escaped your hands when you attempted to seize him, you foolishly think that you can again grasp him thundering from heaven? Indeed, I do not seek my glory; there is one who seeks and judges. Let it seem absurd to no one that a dead dog or a flea bears the Lord's figure, since in another place due to the frailty of the flesh, which he received from a virgin's flesh without male seed, he says of himself: "But I am a worm, and not a man" (Psalm XXII). And due to the glory of the resurrection, which he quickly and swiftly completed from death to life as if by a leap: "And I am shaken out as a locust" (Psalm CVIII).
[AD 585] Cassiodorus on 1 Samuel 24:14