As my Father appointed a kingdom for me, so do I appoint for you that you may eat and drink at my table in my kingdom, and sit on thrones judging the twelve tribes of Israel. 282
Catechism number 570
Jesus' entry into Jerusalem manifests the coming of the kingdom that the Messiah-King, welcomed into his city by children and the humble of heart, is going to accomplish by the Passover of his Death and Resurrection.