The next day the great crowd that had come to the festival heard that Jesus was coming to Jerusalem. So they took branches of palm trees and went out to meet him, shouting, "Hosanna! Blessed is the one who comes in the name of the Lord - the King of Israel!"
Jesus found a young donkey and sat on it; as it is written: "Do not be afraid, daughter of Zion. Look, your king is coming, sitting on a donkey's colt!"
His disciples did not understand these things at first; but when Jesus was glorified, then they remembered that these things had been written of him and had been done to him.
-The Gospel of John, 12:12-16