The case for the Trinity has been covered very well.
I can only add Col 1:15-16 NKJV He is the image of the invisible God, the firstborn over all creation. For by Him all things werre created that are in heaven and that are on earth, visible and invisible, whether thrones or dominions or principalities or powers. All things were created through Him and for Him.
Jesus is Creator of the universe.
Genesis 1:2 And the Spirit of God was hovering over the face of the waters. The Holy Spirit is Creator.
Gen 1:26 Then God said, "Let US make man in OUR image, according to OUR likeness: Thus the Three are mentioned as Creator. Deut. 6:4 Hear O Israel: The LORD our God, the LORD is One!"
In John 8:58 Most assuredly I say to you, before Abraham was, I AM. By claiming to be the I AM who spoke to Moses from the burning bush, He was claiming to be God. That is why the Jews took up rocks to stone Him to death in the next verse.
Our God is Father, Son and Holy Spirit, one God and One Creator, in 3 persons.
I was raised in a church that denied the trinity and had taken every mention of the word out of the hymnal. It was a very liberal Disciples of Christ (Christian) church. I finally learned the truth in a Lutheran church. The understanding of our Triune God opened up the scriptures to me to much greater understanding. Prior to that I had been convicted of sin, repented and made restitution, read the New Testament entirely, all due to the leading of the Holy Spirit when I didn't even know there was a Holy Spirit. I had publicly confessed Jesus as my Savior and Lord and was baptized.
But I felt so cheated that my home church denied the Trinity and refused to reveal just Who God is. They even made light of the Lord's Supper, not even using scriptures that in any way pertained to it when serving it. We were not admonished to discern the Lord's Body and Blood or to search ourselves and confess our sins before partaking. They just passed out the elements. It all seemed so empty. I never heard the Gospel preached there till a new youth pastor came. That church has died back to a dozen people from 400. It is a dead church. No surprise.