Isaiah 45:5,6 (KJV)
5 I am the Lord, and there is none else, there is no God beside me: I girded thee, though thou hast not known me:
6 That they may know from the rising of the sun, and from the west, that there is none beside me. I am the Lord, and there is none else.
Isaiah 45:20-23 (KJV)
20 Assemble yourselves and come; draw near together, ye that are escaped of the nations: they have no knowledge that set up the wood of their graven image, and pray unto a god that cannot save.
21 Tell ye, and bring them near; yea, let them take counsel together: who hath declared this from ancient time? who hath told it from that time? have not I the Lord? and there is no God else beside me; a just God and a Saviour; there is none beside me.
22 Look unto me, and be ye saved, all the ends of the earth: for I am God, and there is none else.
23 I have sworn by myself, the word is gone out of my mouth in righteousness, and shall not return, That unto me every knee shall bow, every tongue shall swear.
1 Corinthians 8:3-6 (KJV)
3 But if any man love God, the same is known of him.
4 As concerning therefore the eating of those things that are offered in sacrifice unto idols, we know that an idol is nothing in the world, and that there is none other God but one.
5 For though there be that are called gods, whether in heaven or in earth, (as there be gods many, and lords many,)
6 But to us there is but one God, the Father, of whom are all things, and we in him; and one Lord Jesus Christ, by whom are all things, and we by him.