Hosanna to the Son of David: Blessed is He that cometh in the name of the Lord; Hosanna in the highest. – Matthew 21:9

Jesus had frequently avowed His mission in plain speech; He had told them who He was, and why He came; but they would not hear; so that they dared to say to Him, “If Thou be the Christ tell us plainly.” He had plainly told them times without number. Now He will assure them still more positively of His kingdom by openly riding into the city of Jerusalem in state. Now shall they see that He claims to be the Messiah, sent of God, of whom the prophet said, “Say ye to the daughter of Zion, Behold, thy salvation cometh.” Out of the mouths of babes and sucklings shall His fame be proclaimed; multitudes of people shall acknowledge with loud voices that “He cometh in the name of the Lord”; until the envious Pharisees shall be driven to ask, “Hearest Thou what these say?” You will remember that our Lord rode into Jerusalem as a King, but He was also brought there as the Lamb of God’s Passover, whose blood must save the people. It was not meet that the Lamb of God should go to the altar without observation; it was not fit that He who taketh away the sin of the world should be led to the temple unobserved. The day was near when He was to be offered up, and all eyes were called to look on Him and know who and what He was. Therefore, He permitted this great gathering and this honorable attention to Himself, that He might say to Israel, by deeds as well as by words, “I am He that should come. I am He who of old had said, Lo, I come: in the volume of the book it is written of Me, I delight to do Thy will, O My God.” When they crucified Him the rulers knew what He professed to be. Albeit many of them were in ignorance as to the truthfulness of His claims, yet they knew right well that they were crucifying the One who professed to be the Lord of glory, the One who was acknowledged to be the Son of David, the One who had in public avowed Himself to be King in Zion. – C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2196.cfm