New Defender's Study Bible Notes
7:14 now are they holy. If one member of the marriage is a believer, then he or she has been “sanctified”—that is, “set apart” in a special relation—unto God. By that very fact, then both the unbelieving spouse and their children have also been “set apart,” inevitably sharing some of the blessings that God promises the believing partner. The most obvious such blessing is the greater possibility that the children, as well as the non-Christian spouse, will be won to Christ by the believing spouse (I Corinthians 7:16).