Galatians 3:20

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

1 Timothy 2:5

For there is one God, one mediator also between God and men, himself man, Christ Jesus,

Deuteronomy 6:4

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

Hebrews 8:6

But now hath he obtained a ministry the more excellent, by so much as he is also the mediator of a better covenant, which hath been enacted upon better promises.

Hebrews 9:15

And for this cause he is the mediator of a new covenant, that a death having taken place for the redemption of the transgressions that were under the first covenant, they that have been called may receive the promise of the eternal inheritance.

Hebrews 12:24

and to Jesus the mediator of a new covenant, and to the blood of sprinkling that speaketh better than that of Abel.

Genesis 15:18

In that day Jehovah made a covenant with Abram, saying, Unto thy seed have I given this land, from the river of Egypt unto the great river, the river Euphrates:

Genesis 17:1-2

And when Abram was ninety years old and nine, Jehovah appeared to Abram, and said unto him, I am God Almighty; walk before me, and be thou perfect.

Job 9:33

There is no umpire betwixt us, That might lay his hand upon us both.

Acts 12:20

Now he was highly displeased with them of Tyre and Sidon: and they came with one accord to him, and, having made Blastus the king's chamberlain their friend, they asked for peace, because their country was fed from the king's country.

Romans 3:29-30

Or is God the God of Jews only? is he not the God of Gentiles also? Yea, of Gentiles also:

Galatians 3:17

Now this I say: A covenant confirmed beforehand by God, the law, which came four hundred and thirty years after, doth not disannul, so as to make the promise of none effect.

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 umpire betwixt us, That might lay his hand upon us both.
Acts 12:20
Now he was highly displeased with them of Tyre and Sidon: and they came with one accord to him, and, having made Blastus the king's chamberlain their friend, they asked for peace, because their country was fed from the king's country.
1 Timothy 2:5
For there is one God, one mediator also between God and men, himself man, Christ Jesus,

But

Galatians 3:17
Now this I say: A covenant confirmed beforehand by God, the law, which came four hundred and thirty years after, doth not disannul, so as to make the promise of none effect.
Genesis 15:18
In that day Jehovah made a covenant with Abram, saying, Unto thy seed have I given this land, from the river of Egypt unto the great river, the river Euphrates:
Genesis 17:1
And when Abram was ninety years old and nine, Jehovah appeared to Abram, and said unto him, I am God Almighty; walk before me, and be thou perfect.
Deuteronomy 6:4
Hear, O Israel: Jehovah our God is one Jehovah:
Romans 3:29
Or is God the God of Jews only? is he not the God of Gentiles also? Yea, of Gentiles also:

General references

Deuteronomy 5:3
Jehovah made not this covenant with our fathers, but with us, even us, who are all of us here alive this day.
Romans 3:30
if so be that God is one, and he shall justify the circumcision by faith, and the uncircumcision through faith.
James 2:19
Thou believest that God is one; thou doest well: the demons also believe, and shudder.

American Standard Version Public Domain