Unity of God: Asserted by God Himself
Source: TTT
Isaiah 44:6, 8
Thus says the LORD, the King and Redeemer of Israel, the LORD of Hosts: “I am the first and I am the last, and there is no God but Me. / Do not tremble or fear. Have I not told you and declared it long ago? You are My witnesses! Is there any God but Me? There is no other Rock; I know not one.”
Isaiah 45:18, 21
For thus says the LORD, who created the heavens—He is God; He formed the earth and fashioned it; He established it; He did not create it to be empty, but formed it to be inhabited: “I am the LORD, and there is no other. / Speak up and present your case—yes, let them take counsel together. Who foretold this long ago? Who announced it from ancient times? Was it not I, the LORD? There is no other God but Me, a righteous God and Savior; there is none but Me.