Galatians 3:20

Now a go-between is not a go-between of one; but God is one.

1 Timothy 2:5

For there is one God and one peacemaker between God and men, the man Christ Jesus,

Deuteronomy 6:4

Give ear, O Israel: the Lord our God is one Lord:

Hebrews 8:6

But now his position as priest is higher. because through him God has made a better agreement with man, based on the giving of better things.

Hebrews 9:15

And for this cause it is through him that a new agreement has come into being, so that after the errors under the first agreement had been taken away by his death, the word of God might have effect for those who were marked out for an eternal heritage.

Hebrews 12:24

And to Jesus by whom the new agreement has been made between God and man, and to the sign of the blood which says better things than Abel's blood.

Genesis 15:18

In that day the Lord made an agreement with Abram, and said, To your seed have I given this land from the river of Egypt to the great river, the river Euphrates:

Genesis 17:1-2

When Abram was ninety-nine years old, the Lord came to him, and said, I am God, Ruler of all; go in my ways and be upright in all things,

Job 9:33

There is no one to give a decision between us, who might have control over us.

Acts 12:20

Now he was very angry with the people of Tyre and Sidon: and they came to him, all together, and having made friends with Blastus, the controller of the king's house, they made a request for peace, because their country was dependent on the king's country for its food.

Romans 3:29-30

Or is God the God of Jews only? is he not in the same way the God of Gentiles? Yes, of Gentiles:

Galatians 3:17

Now this I say: The law, which came four hundred and thirty years after, does not put an end to the agreement made before by God, so as to make the undertaking without 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 one to give a decision between us, who might have control over us.
Acts 12:20
Now he was very angry with the people of Tyre and Sidon: and they came to him, all together, and having made friends with Blastus, the controller of the king's house, they made a request for peace, because their country was dependent on the king's country for its food.
1 Timothy 2:5
For there is one God and one peacemaker between God and men, the man Christ Jesus,

But

Galatians 3:17
Now this I say: The law, which came four hundred and thirty years after, does not put an end to the agreement made before by God, so as to make the undertaking without effect.
Genesis 15:18
In that day the Lord made an agreement with Abram, and said, To your seed have I given this land from the river of Egypt to the great river, the river Euphrates:
Genesis 17:1
When Abram was ninety-nine years old, the Lord came to him, and said, I am God, Ruler of all; go in my ways and be upright in all things,
Deuteronomy 6:4
Give ear, O Israel: the Lord our God is one Lord:
Romans 3:29
Or is God the God of Jews only? is he not in the same way the God of Gentiles? Yes, of Gentiles:

General references

Deuteronomy 5:3
The Lord did not make this agreement with our fathers but with us, who are all living and present here today.
Romans 3:30
If God is one; and he will give righteousness because of faith to those who have circumcision, and through faith to those who have not circumcision.
James 2:19
You have the belief that God is one, and you do well: the evil spirits have the same belief, shaking with fear.

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain