Matthew 21:9, And the crowds going before Him and the ones following cried out saying: Hosanna to the Son of David; Blessed is the One coming in the Name of the Lord; Hosanna in the highest!
The words the crowd shouts are taken from Psalm 118:25-26. In verse 27 of that Psalm—following immediately after the words of the crowd—we read this:
YHWH is God, and He has made His light to shine upon us. Bind the festal sacrifice with cords, up to the horns of the altar!
So, in Psalm 118, the coming of the salvation of YHWH (v.25-26), the shining of His light upon His people, and the binding of the sacrifice to the altar (v.27) are all united in some way. These concepts are interrelated, and in Matthew’s Gospel, we see how that is so: The King who comes in the Name of YHWH, IS Himself the festal sacrifice who will be bound with cords to the horns of Calvary’s altar. Christ’s triumphal entry as the King of Zion who brings the light and presence and salvation of YHWH IS His approach to the altar as the sacrifice. Or, said another way, the binding of the sacrifice and the leading of that sacrifice to the altar IS the triumphal entry into Zion of the salvific presence of YHWH in the person of His chosen King.
The harmonization of these various passages and their surrounding contexts around the person of Jesus Christ as He enters Jerusalem in triumph and splendor allows us to see this moment with new eyes. The triumphal entry is the ascent to the cross; victory and splendor is the binding of the festal sacrifice to the horns of the altar; the King is the sacrifice; salvation for Zion is the sacrificial death of her King; the light of YHWH’s face shines as the King is bound to the altar; the saving presence of YHWH dwells eschatologically in the midst of His people as the humble King is fastened with cords to the horns of the True Altar on Calvary—thus making that altar into His throne and ark and the heart of the Holy of Holies from which the saving light of the presence of YHWH shines. Hosanna in the highest indeed—it is as the King is lifted up on the altar to the heights of the cross that Salvation in the name of YHWH dawns for Zion.