What then was the sign? He sat on a colt, as we have just heard the blessed Evangelist clearly telling us. Perhaps someone will say, “When he traveled all Judea—for he taught in their synagogues and added the working of miracles to his words—he did not ask for an animal on which to ride. When Christ could have purchased one, he would not, although he often was wearied by his long journeys on the way. When passing through Samaria, he was wearied with his journey, as it is written. Who can make us believe that when he was going from the Mount of Olives to Jerusalem, places separated from one another by so short an interval, that he would require a colt? Since the mother accompanied the colt, why did he not take the mother instead of choosing the colt? The donkey that bore the colt was brought to him also. We learn this from the words of Matthew, who says that he sent the disciples to a village opposite them. He said to them, “You will find a donkey tied and a colt with her. Untie and bring them to me:””They brought,” it says,”the donkey and the colt with her.”‘ We must consider, therefore, what are the explanations and the benefits that we derive from this occurrence and how we make Christ riding on the colt a type of the calling of the Gentiles. The colt of a donkey is mounted on which none has sat, because no one before Christ called the peoples of the nations to the church.
Cyril of Alexandria
Commentary on Luke, Homily 130