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