Hosanna in the Highest: blessed is he who comes in the name of the Lord!

Jesus Christ is the fulfillment of God’s covenant with David

Matthew 21:9 ESV
[9] And the crowds that went before him and that followed him were shouting, “Hosanna to the Son of David! Blessed is he who comes in the name of the Lord! Hosanna in the highest!”

https://bible.com/bible/59/mat.21.9.ESV

Revelation 7:10 NLT
[10] And they were shouting with a great roar, “Salvation comes from our God who sits on the throne and from the Lamb!”

https://bible.com/bible/116/rev.7.10.NLT

Psalms 118:25-26 NLT
[25] Please, Lord, please save us. Please, Lord, please give us success. [26] Bless the one who comes in the name of the Lord. We bless you from the house of the Lord.

https://bible.com/bible/116/psa.118.25-26.NLT

Matthew 20:30 NLT
[30] Two blind men were sitting beside the road. When they heard that Jesus was coming that way, they began shouting, “Lord, Son of David, have mercy on us!”

https://bible.com/bible/116/mat.20.30.NLT

The Davidic Covenant, as established in 2 Samuel 7, is a promise from God to David that his lineage would be a source of kingship and everlasting reign. In Christian theology, this promise is understood to be fulfilled in Jesus Christ, who is seen as the ultimate descendant of David and the true heir to the throne.

Scripture indicates that Christ will fulfill the Davidic Covenant by reigning over a kingdom that is political in nature. First, Isaiah 9:6–7 states that when the Messiah sits on David’s throne ruling His kingdom, the government will be upon His shoulder, and the increase of His government will have no end.

The Fulfillment of God’s Covenants with Abraham and David

https://bible.org/seriespage/7-fulfillment-davidic-covenant

In Christ, we have the fulfillment of these eternal promises (covenants) made through Abraham, King David and others, that the Heir of the promise has come, and we, as joint heirs with Christ, become the beneficiaries of the fulfilled promises, which is the salvation and redemption of God’s chosen people, the children of God. Those who repent and believe in Him, in His name, are adopted as children of God; children and joint heirs with Christ of eternity.

Galatians 3:27-29 NLT
[27] And all who have been united with Christ in baptism have put on Christ, like putting on new clothes. [28] There is no longer Jew or Gentile, slave or free, male and female. For you are all one in Christ Jesus. [29] And now that you belong to Christ, you are the true children of Abraham. You are his heirs, and God’s promise to Abraham belongs to you.

https://bible.com/bible/116/gal.3.27-29.NLT