Bible Verses About Unity of God: God himself

Thus said Jehovah, king of Israel, And his Redeemer, Jehovah of Hosts: `I am the first, and I the last, And besides Me there is no God.

Fear not, nor be afraid, Have I not from that time caused thee to hear, and declared? And ye are My witnesses, Is there a God besides Me? yea, there is none, A Rock I have not known.

For thus said Jehovah, Creator of heaven, He is God, Former of earth, and its Maker, He established it--not empty He prepared it, For inhabiting He formed it: `I am Jehovah, and there is none else.

Declare ye, and bring near, Yea, they take counsel together, Who hath proclaimed this from of old? From that time hath declared it? Is it not I--Jehovah? And there is no other god besides Me, A God righteous and saving, there is none save Me.