Bible Verses About Unity of God: God himself

Thus saith Jehovah, the King of Israel, and his Redeemer, Jehovah of hosts: I am the first, and I am the last; and besides me there is no God.

Fear ye not, neither be afraid: have I not declared unto thee of old, and showed it? and ye are my witnesses. Is there a God besides me? yea, there is no Rock; I know not any.

For thus saith Jehovah that created the heavens, the God that formed the earth and made it, that established it and created it not a waste, that formed it to be inhabited: I am Jehovah; and there is none else.

Declare ye, and bring it forth; yea, let them take counsel together: who hath showed this from ancient time? who hath declared it of old? have not I, Jehovah? and there is no God else besides me, a just God and a Saviour; there is none besides me.