Galatians 3:20

But there cannot be a mediator where only one individual is concerned.

1 Timothy 2:5

For there is but one God and but one Mediator between God and men--Christ Jesus, Himself man;

Hebrews 8:6

But, as a matter of fact, the ministry which Christ has obtained is all the nobler a ministry, in that He is at the same time the negotiator of a sublimer covenant, based upon sublimer promises.

Hebrews 9:15

And because of this He is the negotiator of a new Covenant, in order that, since a life has been given in atonement for the offences committed under the first Covenant, those who have been called may receive the eternal inheritance which has been promised to them.

Hebrews 12:24

and to Jesus the negotiator of a new Covenant, and to the sprinkled blood which speaks in more gracious tones than that of Abel.

Acts 12:20

Now the people of Tyre and Sidon had incurred Herod's violent displeasure. So they sent a large deputation to wait on him; and having secured the good will of Blastus, his treasurer, they begged the king to be friendly with them again, because their country was dependent on his for its food supply.

Romans 3:29-30

Is God simply the God of the Jews, and not of the Gentiles also? He is certainly the God of the Gentiles also,

Galatians 3:17

I mean that the Covenant which God had already formally made is not abrogated by the Law which was given four hundred and thirty years later--so as to annul the promise.

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
Now the people of Tyre and Sidon had incurred Herod's violent displeasure. So they sent a large deputation to wait on him; and having secured the good will of Blastus, his treasurer, they begged the king to be friendly with them again, because their country was dependent on his for its food supply.
1 Timothy 2:5
For there is but one God and but one Mediator between God and men--Christ Jesus, Himself man;

But

Galatians 3:17
I mean that the Covenant which God had already formally made is not abrogated by the Law which was given four hundred and thirty years later--so as to annul the promise.
Romans 3:29
Is God simply the God of the Jews, and not of the Gentiles also? He is certainly the God of the Gentiles also,

General references

Romans 3:30
unless you can deny that it is one and the same God who will pronounce the circumcised to be acquitted on the ground of faith, and the uncircumcised to be acquitted through the same faith.
James 2:19
You believe that God is one, and you are quite right: evil spirits also believe this, and shudder."