What Does the Bible Say About the Unity of God?

Deuteronomy 4:35 American Standard Version (ASV)
35 Unto thee it was showed, that thou mightest know that Jehovah he is God; there is none else besides him.

Israel was shown these things so they might appreciate the uniqueness of their God. Jehovah alone is God, and besides him there is no other. God went to unusual lengths to reveal himself to Israel, and he did so for a significant reason—to discipline them. The expression suggests not punishment or retribution but profound instruction. God’s intent was didactic not judicial. He made them hear his voice… from out of the fire so they might understand that he tolerates no rivals.