In the Bible, God is never a trinity. Neither in Hebrew Scriptures, nor the New Testament is God ever a Trinity.
God is never declared to be triune by anyone in the Bible: not by Moses, the prophets, Jesus or the apostles. No one in the Bible ever mentions the “mystery” about the Triune nature (persons) of God. The Bible never records any opposition to the Triune nature of God being proclaimed – because no one in the Bible proclaimed God as triune. The claim that God is “three-in-one” comes from centuries after the time of Jesus.
As a sample of the Biblical view of God, we read some of Ephesians 1.
Who is God in the passage? Never the Trinity.
Note the singular pronouns used of God. God is never more than one self.
Note the differentiation between God and the Lord (Adon) Jesus Christ.
Note that the Lord Jesus Christ has a God. The Lord Jesus Christ’s God is the Father.
For the Apostle Paul, the one God was not the Trinity. The one God was the Father, the God and Father of our Lord Jesus Christ (cf. 1 Corinthians
8:6).
Other related podcasts:
Is the Trinity in the Bible? If so, Where?
https://www.youtube.com/watch?v=POVaZX3urdc
Part 2: If the Bible is Right, God is NOT a Trinity
https://youtu.be/2x81JF9sKqc
How and When was the Trinity Revealed?
https://www.youtube.com/watch?v=6HaqhjicWv8
The Trinity is NOT Revealed in the Bible (one minute short)
https://studio.youtube.com/video/r8uOyHDqUvY/edit
The Myster of the Trinity: Solved!
https://www.youtube.com/watch?v=cPK-_kVHnB0&t=498s