John 17:3
And this is life eternal, to know thee, the only true God, and Jesus Christ, whom thou hast sent.
Mark 12:29-32
And Jesus answered him, The first of all the commandments is, Hear, O Israel; the Lord our God is one Lord.
1 Timothy 2:5
For there is one God, one mediator also between God and men,
John 10:30
I and the Father are one.
1 Corinthians 8:4-6
we know that an idol is nothing in the world, and that there is no God but one.
Treasury of Scripture Knowledge
Bible References
General references
James 2:19
Thou believest there is one God: thou dost well: the devils also believe and tremble.