The "one God"

(1 Timothy 2:5) 5 For there is one God, and one mediator between God and men, a man, Christ Jesus. . .

(Ephesians 4:6) . . .one God and Father of all [persons], who is over all and through all and in all.

(1 Corinthians 8:6) . . .there is actually to us one God the Father, out of whom all things are, and we for him; and there is one Lord, Jesus Christ, through whom all things are, and we through him.

These texts are the 3 instances in which the phrase "one God" is stated in the Bible. In each and every instance the "one God" is explicitly identified as the Father except in 1 Timothy where it is through context.

Since the Father is the "one God" of the Bible, on what basis do Trinitarians change the Bible's own definition of who God is?

(Matthew 15:3-6) . . .In reply he said to them: “Why is it YOU also overstep the commandment of God because of YOUR tradition? 4 For example, God said, ‘Honor your father and your mother’; and, ‘Let him that reviles father or mother end up in death.’ 5 But YOU say, ‘Whoever says to his father or mother: “Whatever I have by which you might get benefit from me is a gift dedicated to God,” 6 he must not honor his father at all.’ And so YOU have made the word of God invalid because of YOUR tradition.