The concept of the Trinity is the very concept of the existence of God, and since God reveals himself to his children, it only makes sense that all Christian churches would believe in and defend the doctrine of the Trinity. This means that God, a singular being, exists in a plural manner. God's very name implies His triune existence. Note also, that all Hebrew letters have a numeric value, all Hebrew words also have value. Just as God is composed of three, so is man.
Man is composed of a body, a soul, and a spirit.
We all know man to be one being, not three, in spite of his triune composition. The body is separate from the soul which is separate from the spirit, however they still make one man. Man was only one of God's many creations. God is the creator of the entire universe. Just as God created man in His own image, he had also created the universe in the same fashion.