John Calvin Commentary 2 Corinthians 1:18

"But as God is faithful, our word toward you is not yea and nay." — 2 Corinthians 1:18 (ASV)

God is faithful. By the term word he means doctrine, as is evident from the reason he adds when he says that the Son of God, who is preached by him, is not variable, etc. Regarding his consistent doctrine, not differing from himself, he intends that by this they should form a judgment of his integrity, and in this way he removes every unfavorable suspicion of fickleness or unfaithfulness.

It does not, however, necessarily follow that the man who is faithful in doctrine is also observant of truth in all his words. But as Paul did not consider it very important how he was regarded, provided only that the majesty of his doctrine remained safe and sound, he, for that reason, calls the Corinthians' attention chiefly to that matter.

He intimates, it is true, that he maintained in his whole life the same course of fidelity as the Corinthians had seen in his ministry. He seems, however, intentionally, in repelling the slander, to transfer it from his person to his doctrine, because he was unwilling that his apostleship should be indirectly defamed, while he was not greatly concerned about himself in other respects.

But observe with what zeal he applies himself to this. For he calls God to witness how simple and pure his preaching was — not ambiguous, not variable, not temporizing. In his oath, too, he connects the truth of God with the truth of his doctrine: “The truth of my preaching is as sure and stable as God is faithful and true.”

This is not surprising, for the word of God, which Isaiah says endureth for ever, (Isaiah 40:8), is nothing other than what prophets and apostles published to the world, as Peter explains it (1 Peter 1:25). Hence also his confidence in denouncing a curse upon angels if they dared to bring another gospel, one that was at variance with his (Galatians 1:8). Who would dare to make the angels of heaven subject to his doctrine if he did not have God as his authority and defense? With such an assurance of a good conscience should ministers be endowed, who mount the pulpit to speak the word in Christ’s name — so as to feel assured that their doctrine can no more be overthrown than God himself.