Matthew 21:7–9

Christ is said to be “coming” as one who came from above: being God by nature and Son of the Father, he became man and came in the Lord’s name, being called Lord. So as God by nature he is called blessed — that is, glorified. Christ was sitting on the colt, and the mother followed. What was done was a sign for us of a most necessary matter: Christ rested on the new people that once worshiped idols, and in due times the Jews’ synagogue will also follow — though in the time of the call it had the older place, having been called first through Moses and the prophets. But because it struck against the saving God, it justly comes behind the colt only with difficulty and has become a tail — that is, an attendant behind those from the nations — and the first has become last.

See how he who knows “kidneys and hearts” showed human nature carried into the last irrationality: both the Jews’ synagogue and the multitude of the nations are likened to a donkey, the most irrational of all. For some “served the creation rather than the Creator” God, and others, dishonoring the tutoring law, went outside good mind and understanding and turned toward every form of baseness; “they were compared to senseless cattle and made like them,” according to the psalmist’s voice. A donkey is also otherwise a symbol of uncleanness; for the animal is unholy and has condemnation from the law. Such are all who wander and love sin.