Jesus is the OT God. There's no such thing as OT God and NT God. He is the same, the Father, Son and Holy Spirit.
Genesis 1:1 In the beginning, God created the heavens and the earth.
John 1:1 In the beginning was the Word, and the Word was with God, and the Word was God. 2 He was in the beginning with God. 3 All things were made through him, and without him was not any thing made that was made. 4 In him was life,[
a] and the life was the light of men.
Few on many examples of the trinity in OT
Genesis 1:26 Then God said, “Let us make man[
h] in our image, after our likeness.
Psalm 45:7 Therefore God, your God, has anointed you
Psalm 110:1
The Lord says to my Lord: “Sit at my right hand, until I make your enemies your footstool.”
Zechariah 3:2 And the Lord said to Satan, “The Lord rebuke you, O Satan!
It is a great mistake to ignore the OT, as the Bible is one book. Could we even believe Jesus is who He claim HE is without OT? I do not think so.