John Lightfoot on Matthew 21:5

[Meek, and sitting upon an ass.] This triumph of Christ completes a double prophecy: 1. This prophecy of Zechariah here mentioned. 2. The taking to themselves the Paschal lamb, for this was the very day on which it was to be taken, according to the command of the law, Exodus 12:3; "In the tenth day of this month, they shall take to them every man a lamb."

It scarce appears to the Talmudists, how those words of Daniel concerning the Messias, that "he comes with the clouds of heaven," are consistent with these words of Zechariah, that "he comes sitting upon an ass." "If (say they) the Israelites be good, then he shall come with the clouds of heaven; but if not good, then riding upon an ass." Thou art much mistaken, O Jew: for he comes "in the clouds of heaven," as judge and revenger; but sitting upon an ass, not because you are, but because he is, good. "King Sapores said to Samuel, 'You say your Messias will come upon an ass, I will send him a brave horse.' He answers him, 'You have not a horse with a hundred spots as is his ass." In the greatest humility of the Messias they dream of grandeur, even in his very ass.