John 17:3
And this is eternal life, to know thee, the only true God, and Jesus Christ whom thou hast sent.
Mark 12:29-32
Jesus replied. "The first is. 'Hear, O Israel, the Lord our God is one Lord;
1 Timothy 2:5
For God is one; and one is mediator between God and man, the Man Christ Jesus,
John 10:30
"I and my Father are one."
1 Corinthians 8:4-6
Now as to eating food that has been offered to idols, we know well that an idol has no real existence in the universe, and that there is no God but One.
Treasury of Scripture Knowledge
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James 2:19
You believe that God is one? You do well; even the demons believe, and they shudder.