Genesis 20:7

7.Now therefore, restore the man his wife. God does not now speak of Abraham as of a common man, but as of one who is so peculiarly dear unto himself, that He undertakes the defense of his conjugal bed, by a kind of privilege. He calls Abraham a prophet, for the sake of honor; as if he were charging Abimelech with having injured a man of great and singular excellence; that he might not wonder at the greatness of the punishment inflicted upon him. And although the word prophet is properly the name of an office; yet I think it has here a more comprehensive import, and that it is put for a chosen man, and one who is familiar with God. For since at that time, no Scripture was in existence, God not only made himself known by dreams and visions but chose also to himself rare and excellent men, to scatter abroad the seed of piety, by which the world would become more inexcusable. But since Abraham is a prophet, he is constituted, as it were, a mediator between God and Abimelech. Christ, even then, was the only Mediator; but this was no reason why some men should not pray for others; especially they who excelled in holiness, and were accepted by God; as the Apostle teaches, that

‘the fervent prayers of a righteous man avail much.’
(James 5:16.)

And we ought not, at this day, to neglect such intercession, provided it does not obscure the grace of Christ, nor lead us away from Him. But that, under this pretext, the Papists resort to the patronage of the dead, is absurd. For as the Lord does not here send the king of Gerar to Noah, or to any one of the dead fathers, but into the presence of the living Abraham; so the only precept we have on this subject is, that, by mutually praying for each other, we should cultivate charity among ourselves.

And if thou restore her not. Hence we are to learn, the intention of those threats and denunciations with which God terrifies men; namely, forcibly to impel those to repentance, who are too backward. In the beginning of this discourse, it had been absolutely declared, ‘Thou art a dead man;’ now the condition is added, ‘Unless thou restore her.’ Yet the meaning of both expressions is the same; though at first God speaks more sharply, that he may inspire the offender with the greater terror. But now, when he is subdued, God expresses his intention more clearly, and leaves him the hope of pardon and salvation. Thus is the knot untied, with which many entangle themselves, when they perceive that God does not always, or instantly, execute the punishments which he has denounced; because they deem it a sign, either that God has changed his purpose, or that he pretends a different thing by his word, from that which he has secretly decreed. He threatens destruction to the Ninevites, by Jonah, and afterwards spared them. (Jonah 3:4.) The unskilful do not perceive how they can escape from one of two absurdities; namely, that God has retracted his sentence; or that he had feigned himself to be about to do what he really did not intend. But if we hold fast this principle, that the inculcation of repentance is included in all threats, the difficulty will be solved. For although God, in the first instance, addresses men as lost; and, therefore, penetrates them with the present fear of death, still the end is to be regarded. For if he invites them to repentance, it follows, that the hope of pardon is left them, provided they repent.