Adam Clarke on 1 Timothy 2:5

There is one God - Who is the maker, governor, and preserver of all men, of every condition, and of every nation, and equally wills the salvation of all.

And one mediator - The word μεσιτης, mediator, signifies, literally, a middle person, one whose office it is to reconcile two parties at enmity; and hence Suidas explains it by ειρηνοποιος, a peace-maker. God was offended with the crimes of men; to restore them to his peace, Jesus Christ was incarnated; and being God and man, both God and men met in and were reconciled by him. But this reconciliation required a sacrifice on the part of the peace-maker or mediator; hence what follows.