This type of public procession was common in the ancient world. A king or conquering general would ride into town on a powerful steed and be hailed by the cheering crowds.
However, Jesus departed from this script in one very significant way. Instead of entering Jerusalem on a magnificent horse, he rode on a polos, a colt or small donkey. So here was Jesus Christ, the very Son of God, the authoritative and majestic King of King, riding on a mount fit for a hobbit or child. Why would he do that? He was laying claim to a prophecy found in Zechariah 9:9 . . .
Rejoice greatly, O Daughter of Zion! Shout, Daughter of Jerusalem! See, your King comes to you, righteous and having salvation, gentle and riding on a donkey, on a colt, the foal of a donkey.So, at the outset of Holy Week, we are reminded that Jesus is a King, but he is unlike any king the world has ever known. His Kingdom is coming, but it is not like the kingdoms of this world. He will conquer, but his conquest does not come through military or political violence. Rather, his victory comes only as he willingly endures that kind of violence.