Mark 12:32

The expert in the law of Moses said to Jesus, "Truly, Teacher, you are right in saying that God is [the only] one and that there is no other God but Him.

Mark 12:29

And Jesus answered, "The foremost one is this [Deut. 6:4-5], 'Hear this, you Israelites, the Lord our God is the only Lord,

1 John 5:20-21

And [in addition], we know that the Son of God has come [in a physical body, See 4:2] and has given us understanding, so that we can know the True One [i.e., God], and that we are in [fellowship with] the True One, even His Son Jesus Christ. This Son is the true God and eternal life.

Treasury of Scripture Knowledge

Summary

Unto thee it was shewed, that thou mightest know that the LORD he is God; there is none else beside him.

Bible References

None else

Mark 12:29
And Jesus answered, "The foremost one is this [Deut. 6:4-5], 'Hear this, you Israelites, the Lord our God is the only Lord,
1 John 5:20
And [in addition], we know that the Son of God has come [in a physical body, See 4:2] and has given us understanding, so that we can know the True One [i.e., God], and that we are in [fellowship with] the True One, even His Son Jesus Christ. This Son is the true God and eternal life.