But to the rest speak I, not the Lord: If any brother has a wife that believes not, and she be pleased to dwell with him, let him not put her away.
All Commentaries on 1 Corinthians 7:12 Go To 1 Corinthians 7
Tertullian of Carthage
AD 220
The ground of that passage of the first (Epistle) to the Corinthians, where it is written: If any of the brethren has an unbelieving wife, and she consents to the matrimony, let him not dismiss her; similarly, let not a believing woman, married to an unbeliever, if she finds her husband agreeable (to their continued union), dismiss him: for the unbelieving husband is sanctified by the believing wife, and the unbelieving wife by the believing husband; else were your children unclean."