If the Messiah had to be God and God is triune in nature, then there need be no question if Messiah Yeshua (Jesus the Christ) is God.
When we compare the descriptions of God in the Hebrew Bible (Old Testament) with the New Covenant (New Testament) we see that God the Father, God the son and God the Holy Spirit are the same in character and essence. The God of Mt Sinai is the God of Calvary.
Now the Lord descended in the cloud and stood with him there, and proclaimed the name of the Lord. And the Lord passed before him and proclaimed, “The Lord, the Lord God, merciful and gracious, longsuffering, and abounding in goodness and truth.”
The first word God uses to describe Himself is “rachamim” which means “compassion.” The same is used to describe Jesus:
For we do not have a High Priest who cannot sympathize with our weaknesses, but was in all points tempted as we are, yet without sin. Let us therefore come boldly to the throne of grace that we may obtain mercy and find grace to help in time of need.
God abounds in “grace and truth,” or in Hebrew “emet v’hesed.” Whereas God gave Israel His grace and truth by Moses, Yeshua BECAME grace and truth. (The word “but” was added by the translators and distorts the meaning of the verse):
For the law was given through Moses, grace and truth came through Jesus Christ.