 And the woman which has a husband who believes not, if he's pleased to dwell with her, let her not leave him. For the unbelieving husband is sanctified by the wife, and the unbelieving wife is sanctified by the husband. Else were your children unclean, but now they are holy. What he's saying there is that that relationship has a sanctifying effect on that person. That doesn't mean that they're saved just because you're a believer. They still have to come to Christ themselves. But their overall life will be so much more blessed.