Titus of Bostra

They who had tied the ass are struck dumb, because of the greatness of His mighty power, and are unable to resist the words of the Saviour; for "the Lord" is a name of majesty, and as a King was He about to come in the sight of all the people.

Catena Aurea by Aquinas ↗

Bede

And as they were loosing the colt, its owners said to them: Why are you loosing the colt? For it had many owners, being not devoted to one doctrine and superstition, but wretchedly carried off to various and diverse errors of idols at the whim of unclean spirits, proceeding as it was led. Finally, it is said to be common by a certain vernacular Scripture custom that which is unclean, as also a voice from heaven says to Peter: What God has cleansed, you must not call common (Acts XI). …

On the Gospel of Luke ↗

Bonaventure

Second, as regards the obedience of the disciples carrying out the command, it is added: And as they were loosing the colt, the owners thereof said to them: Why do you loose the colt? by the handling of another's property; and they are called several owners because according to the historical truth, both the she-ass and the colt are said to have belonged to that entire village, and were used by the poor for carrying water.

Commentary on Luke, Chapter 19 ↗