Galatians 3:20

But the Mediator is not a mediator of one, but God is one.

1 Timothy 2:5

For God is one, and there is one Mediator of God and of men, the Man Christ Jesus,

Deuteronomy 6:4

Hear, O, Israel. Jehovah our God is one Jehovah.

Hebrews 8:6

But now He has obtained a more excellent ministry, by so much He is also the Mediator of a better covenant, which was built upon better promises.

Hebrews 9:15

And for this cause He is the Mediator of the new covenant, so that by means of death, for the redemption of the transgressions that were under the first covenant, those who are called might receive the promise of eternal inheritance.

Hebrews 12:24

and to Jesus the Mediator of the new covenant, and to blood of sprinkling that speaks better things than that of Abel.

Genesis 15:18

In the same day Jehovah made a covenant with Abram, saying, I have given this land to your seed, from the river of Egypt to the great river, the river Euphrates,

Genesis 17:1-2

And when Abram was ninety-nine years old, Jehovah appeared to Abram and said to him, I am the Almighty God! Walk before Me and be perfect.

Job 9:33

there is no mediator between us, who might lay his hand on us both.

Acts 12:20

And Herod was in bitter hostility with the men of Tyre and Sidon. But they came to him with one accord and, having made Blastus (who had charge of the king's bedroom) their friend, desired peace, because their country was fed by the king's country.

Romans 3:29-30

Or is He the God of the Jews only, and not also of the nations? Yes, of the nations also,

Galatians 3:17

And I say this, A covenant having been ratified by God in Christ, the Law (coming into being four hundred and thirty years after) does not annul the promise, so as to abolish it.

Treasury of Scripture Knowledge

Summary

Now a mediator is not a mediator of one, but God is one.

Bible References

A mediator is

Job 9:33
there is no mediator between us, who might lay his hand on us both.
Acts 12:20
And Herod was in bitter hostility with the men of Tyre and Sidon. But they came to him with one accord and, having made Blastus (who had charge of the king's bedroom) their friend, desired peace, because their country was fed by the king's country.
1 Timothy 2:5
For God is one, and there is one Mediator of God and of men, the Man Christ Jesus,

But

Galatians 3:17
And I say this, A covenant having been ratified by God in Christ, the Law (coming into being four hundred and thirty years after) does not annul the promise, so as to abolish it.
Genesis 15:18
In the same day Jehovah made a covenant with Abram, saying, I have given this land to your seed, from the river of Egypt to the great river, the river Euphrates,
Genesis 17:1
And when Abram was ninety-nine years old, Jehovah appeared to Abram and said to him, I am the Almighty God! Walk before Me and be perfect.
Deuteronomy 6:4
Hear, O, Israel. Jehovah our God is one Jehovah.
Romans 3:29
Or is He the God of the Jews only, and not also of the nations? Yes, of the nations also,

General references

Deuteronomy 5:3
Jehovah did not make this covenant with our fathers, but with us, even us, all of us here, alive today.
Romans 3:30
since it is one God who will justify circumcision by faith, and uncircumcision through faith.
James 2:19
You believe that there is one God, you do well; even the demons believe and tremble.