Explaining the Trinity doctrine in simple terms from the Bible. Monotheism and the Trinity are biblical. The Bible does teach that there is one God, and the Bible teaches that the Father is God, Jesus Christ is God, the Holy Spirit is God. How can one God be 3 persons? How can Jesus be the Son of God and God? Who is the Holy Spirit? Looking at what the Old Testament teaches about the Trinity and what the New Testament teaches about the Trinity. Explaining the Trinity doctrine and Monotheism from the Bible.