1 Corinthians 7:15

7:15 But if the unbeliever wants a divorce, let it take place. In these circumstances the brother or sister is not bound. ¹  God has called you in peace.

1 Corinthians 9:21

9:21 To those free from the law I became like one free from the law (though I am not free from God’s law but under the law of Christ) to gain those free from the law.

[7:15]  ¹ sn Interpreters differ over the implication of the statement the brother or sister is not bound. One view is that the believer is “not bound to continue the marriage,” i.e., not so slavishly tied to the instruction about not divorcing (cf. vv. 10-11) that he or she refuses to face reality when the unbelieving spouse is unwilling to continue the relationship. In this view divorce is allowable under these circumstances, but not remarriage (v. 11 still applies: remain unmarried or be reconciled). The other view is that the believer is “not bound in regard to marriage,” i.e., free to remain single or to remarry. The argument for this view is the conceptual parallel with vv. 39-40, where a wife is said to be “bound” (a different word in Greek, but the same concept) as long as her husband lives. But if the husband dies, she is “free” to marry as she wishes, only in the Lord. If the parallel holds, then not bound in v. 15 also means “free to marry another.”