Why do we believe in only one God
We believe in only one God because according to the testimony of Sacred Scripture, there is only one God and according to the laws of logic, there can be only one.
If there were two gods, then the one God would be a limit on the other; neither of the two would be infinite, neither one perfect; in these respects neither of the two would be God. Israel’s fundamental of God is: “Hear, o Israel: the Lord our God is one Lord” (Deut 6:4). again and again the prophets exhort the people to abandon their false gods and to convert the one God: “For I am God and there is no other” (Is 45:22
Why does God give himself a name?
God gives himself a name so as to make it possible to address him
God does not wish to remain incognito. He does not want to be revered as a “higher being” that is merely sensed or surmised. God wishes to be known and to be called upon as someone real and active. In the burning bush God reveals to Moses his holy name:
YHWH (ex 3:14). God makes it possible for his people to address him, but he remains the hidden God, the present mystery. Ouf of reverence for God, the name of God, was not (and is not) spoken in Israel; the title Adonai (Lord) is substituted. This same word is used by the New Testament when it glorifies Jesus as true God; “Jesus is Lord!”
Why does it mean to say that God is truth?
“God is light and in him is no darkness (1 Jn 1:5)
The truth of God cannot be “proved” or subjected to empirical tests since science cannot make him an object of investigation. And yet God subjects himself to a special sort of proof. We know that God is the truth the basis of the absolute credibility of Jesus. He is “the way and the truth, and the life” (Jn 14:6). Anyone who enters into a relationship with him can fid this out by putting it to the test. If God were not “true” then faith and reason could not have a dialogue with each other. An agreement is possible, however, because God is truth, and the truth is divine.