John Gill, on 1Pet 3:1

Likewise, ye wives, be in subjection to your own husbands,.... As well as subjects to princes, and servants to masters; though not with the same sort of subjection, but what is suitable to the relation they stand in to their husbands; See Gill on Eph 5:22. See Gill on Col 3:18. that if any obey not the word; any husband who is an unbeliever, has no love for the Gospel, and gives no credit to it, but despises, disbelieves, and rejects it, the word of truth, of faith, of righteousness, reconciliation, and salvation. The apostle, though he includes all wives, and exhorts them in general to subjection to their own husbands, yet has a particular regard to such as had unbelieving husbands, and who, on that account, were scrupulous of living with them, and of being in subjection to them; and therefore, as the Apostle Paul also did, he advises them to abide with them, and behave well to them, using much the same argument as he does in Co1 7:10. they also may without the word be won by the conversation of the wives; for though the ordinary way and means of conversion is the word, faith comes by hearing, and hearing by the word; yet it may be sometimes done without it; or however by the agreeable conversation of professors, and so of religious wives, the hearts of such as were averse to Christianity, and the Gospel, as unbelieving husbands, may be so softened, and wrought upon, as to entertain a better opinion of it, and in process of time be inclined to hear and attend it; the consequence of which may prove their conversion, which is a gaming, or winning of souls; and which, as it is for their good, is for the glory of Christ; for as every soul that is delivered from the power of darkness, and is translated into the kingdom of Christ, is a loss to Satan, it is a gain to Christ, and to his church. The Syriac version, instead of "without the word", reads, "without labour"; as if the winning of unbelieving husbands was easily obtained by the conversation of their wives.