If a Christian gets a divorce and remarries, is he or she guilty of a continuous sin for as long as the marriage continues? Should the couple divorce to end the sin of adultery?
Any marriage that takes place following divorce and while the ex-spouse is still alive is formed through an act of adultery, according to Jesus (you can read why in our article on Divorce).
Is the marriage valid? Jesus says yes in Matthew 19:
Notice Jesus' choice of words carefully. Jesus didn't say that the new marriage after divorce is adultery (i.e., that the new marriage was a continuous act of adultery). Instead, Jesus said that the one who enters into a marriage after divorce commits adultery (i.e., the person's choice to enter into the marriage was sinful). So the marriage itself isn't sinful, but the choice to pursue it is, and therefore the new marriage is as legitimate and binding as any other.
In fact, notice Jesus says the man "marries" another woman. If this new marriage wasn't legitimate in God's eyes, then Jesus would not have described it as a marriage. Jesus' choice of words makes clear that a new, legitimate union is formed through an exchange of vows and a "one-flesh" relationship, and therefore a valid covenant is established and must be honored like all marriages. The man and woman in this new marriage are to remain faithful to each other until death. The choice to marry was sinful since it resulted in an act of adultery, but now that it has been formed it must be honored like all marriages.
We can find this principle reflected in many places in the Bible, including in the account of Jacob. Jacob was deceived into marrying Leah instead of Rachel. Later, Jacob wrongly continued to pursue a marriage with Rachel despite already being married to Leah. In the end, Jacob marries Rachel in addition to Leah and two additional women, and God used all four of these marriages to produce the twelve tribes of Israel. In fact, the Bible confirms these women were legitimate wives of Jacob worthy of honor:
Therefore, every marriage is a covenant that must be honored – even if it was formed through an act of adultery.
Secondly, adultery does not refer to the act of sex, per se, but rather to the breaking of a marriage vow through an act of sex. Once a marriage vow has been broken by an act of adultery, it cannot be said to be "re-broken" each time the couple has sex. A covenant can only be broken once, and thereafter it remains broken. There is no way to "continuously" break a covenant no more than we can "continuously" break a glass jar. So while the consequences of adultery may last forever, the act itself is over in a moment.
This same principle applies in other types of sin. For example, murder is a sin that occurs in a moment, yet the consequences continue forever (i.e., the murder victim remains dead thereafter). If a person commits murder, we wouldn't say that the sin of murder is "continuous" for as long as the victim remains dead. Instead, we say the act to kill unlawfully was a sin, and the results last forever. Likewise, adultery occurs when someone remarries following a divorce, but the sin is momentary (though serious). The consequences of that act last a lifetime, because the new marriage cannot be broken.
Finally, when a person remarries following a divorce, that person commits adultery against the first spouse, and at the same time they enter into a legitimate marriage with the new spouse that is binding for life, and therefore that person may not divorce the second spouse to seek reconciliation with the first spouse. To do so would require a second act of adultery. In fact, God's word specificallyt outlaws reconciliation after remariage:
Under the Law given to Israel, a woman who divorces and remarries and then divorces a second time was not permitted to return to her first husband even if he would have her. The woman's second marriage precluded reconciliation with her first husband, because reconciliation with her first husband would require an act of adultery against her second husband. This is further proof to us that God views a second marriage as legitimate and binding.
In summary, every marriage is considered legitimate, and the Lord expects us to honor whatever marriage we have. Even though a second marriage is formed through an act of adultery, the sin of adultery is not ongoing and the new marriage is valid. Therefore, the new marriage must be honored.
If a Christian has divorced, he or she should remain unmarraige and seek reconciliation. If the divorcee's spouse remarries, then reconciliation is no longer possible, but nonetheless the divorcee should remain unmarried. If a divorcee has remarried, he or she should acknowledge and repent of that sin and should honor the new marriage in peace knowing that sin has been forgiven by Christ. From that point forward, commit to remaining faithful to this new marriage until death.