Could be he’s talking about the Matt. 19 passage on divorce, or maybe the I Tim. 3:2 statement.
Verse 15- “But if the unbelieving depart, let him depart. A brother or a sister is not under bondage in such cases: but God hath called us to peace.”
Also Verse 39 is interesting. “The wife is bound by the law as long as her husband liveth; but if her husband be dead, she is at liberty to be married to whom she will; only in the Lord.”