John Calvin Commentary 1 Corinthians 7:16

"For how knowest thou, O wife, whether thou shalt save thy husband? Or how knowest thou, O husband, whether thou shalt save thy wife?" — 1 Corinthians 7:16 (ASV)

For what do you know, O woman? Those who believe that this observation confirms the second part of his statement explain it this way: “An uncertain hope should not detain you,” and so on.

But, in my opinion, the exhortation is drawn from the potential advantage, for it is a great and distinguished blessing if a wife gain her husband (1 Corinthians 9:19).

Now, unbelievers are not in such a hopeless condition that they cannot be brought to believe. They are dead, it is true, but God can even raise the dead.

Therefore, as long as there remains any hope of doing good, and the pious wife does not know but that she may by her holy conversation (1 Peter 3:1) bring her husband back to the way, she should try every means before leaving him. For as long as a man’s salvation is doubtful, it is fitting for us to be prepared rather to hope for the best.

However, regarding his statement that a husband may be saved by his wife, the expression, it is true, is not strictly accurate, as it ascribes to humans what belongs to God; but there is no absurdity in it.

For as God acts effectively through the instruments He uses, He does, in a way, communicate His power to them. Or, at least, He connects it with their service in such a way that what He does, He speaks of as being done by them.

Consequently, He also sometimes ascribes to them the honor that is due to Himself alone. Let us, however, keep in mind that we have nothing in our power, except insofar as we are directed by Him as instruments.