Galatians 3:20

Now mediation implies more than one person, but God is one only.

1 Timothy 2:5

There is but one God, and one mediator between God and men--the man, Christ Jesus,

Hebrews 8:6

But Jesus, as we see, has obtained a ministry as far excelling theirs, as the Covenant of which he is the intermediary, based, as it is, on better promises, excels the former Covenant.

Hebrews 9:15

And that is why he is the intermediary of a new Covenant; in order that, as a death has taken place to effect a deliverance from the offenses committed under the first Covenant, those who have received the Call may obtain the eternal inheritance promised to them.

Hebrews 12:24

to Jesus, the intermediary of a new Covenant, and to the Sprinkled Blood that tells of better things than the blood of Abel.

Acts 12:20

It happened that Herod was deeply offended with the people of Tyre and Sidon, but they went in a body to him, and, having succeeded in winning over Blastus, the Chamberlain, they begged Herod for a reconciliation, because their country was dependent on the King's for its food-supply.

Romans 3:29-30

Or can it be that God is the God only of the Jews? Is not he also the God of the Gentiles?

Galatians 3:17

My point is this--An agreement already confirmed by God cannot be canceled by the Law, which came four hundred and thirty years later, so as to cause the promise to be set aside.

Treasury of Scripture Knowledge

Summary

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

A mediator is

General references

Bible References

A mediator is

Acts 12:20
It happened that Herod was deeply offended with the people of Tyre and Sidon, but they went in a body to him, and, having succeeded in winning over Blastus, the Chamberlain, they begged Herod for a reconciliation, because their country was dependent on the King's for its food-supply.
1 Timothy 2:5
There is but one God, and one mediator between God and men--the man, Christ Jesus,

But

Galatians 3:17
My point is this--An agreement already confirmed by God cannot be canceled by the Law, which came four hundred and thirty years later, so as to cause the promise to be set aside.
Romans 3:29
Or can it be that God is the God only of the Jews? Is not he also the God of the Gentiles?

General references

Romans 3:30
Yes, of the Gentiles also, since there is only one God, and he will pronounce those who are circumcised righteous as the result of faith, and also those who are uncircumcised on their showing the same faith.
James 2:19
It is a part of your Faith, is it not, that there is one God? Good; yet even the demons have that faith, and tremble at the thought.