Romans 7:1-6

Do you not know, brothers (for I am speaking to those who know the law), that the law has authority over a man only as long as he lives? For instance, a married woman is bound by law to her husband as long as he lives. But if her husband dies, she is released from the law of marriage. So then, if she is joined to another man while her husband is still alive, she is called an adulteress; but if her husband dies, she is free from that law and is not an adulteress, even if she marries another man. Therefore, my brothers, you also died to the law through the body of Christ, that you might belong to another, to Him who was raised from the dead, in order that we might bear fruit to God. For when we lived according to the flesh, the sinful passions aroused by the law were at work in our bodies, bearing fruit for death. But now, having died to what bound us, we have been released from the law, so that we serve in the new way of the Spirit, and not in the old way of the written code.

Matthew 19:8-9 

Jesus replied, “Moses permitted you to divorce your wives because of your hardness of heart; but it was not this way from the beginning. Now I tell you that whoever divorces his wife, except for sexual immorality, and marries another woman, commits adultery.”