First, the question assumes that a condition of adultery exists, and in such a case, must the man and the woman separate? The answer cannot be decided upon the basis of emotions or human reasoning, but by what the Bible teaches.
Second, to arrive at a safe conclusion two things are involved: (1) what constitutes adultery-a sinful relationship? and (2) what is required in repentance?
When a man and a woman marry, having the scriptural right to do so, a union is formed and God intends for it to continue as long as both shall live. Marriage, being originated by God (Gen. 2:18-24) must not be broken by man (Matt. 19:6). It is of divine creation and symbolizes the union that exists between Christ and His church (Eph. 5:31-32). This holy relationship must be respected by man, and therefore is not to be looked upon lightly. Being of divine origin and being a holy relationship, it is therefore regulated by the laws of God. A scriptural marriage is one which conforms with God’s laws governing marriage. Conversely, an unscriptural marriage is one which does not conform to His laws. Man can no more stipulate the conditions of marriage or divorce than he can’the conditions of becoming a Christian. God, has set forth those conditions that make marriage right; therefore, man is forbidden to alter them. He must not venture to change with his unholy hands that which God has made sacred and holy.
What constitutes a sinful relationship in marriage? Jesus taught in Matthew 19:9: “...Whosoever shall put away his wife, except for fornication, and shall marry another, committeth adultery: and he that marrieth her when she is put away committeth adultery.” Thus, he who puts away his mate for a cause other than fornication and marries another, commits adultery. Likewise, when one marries her who is put away, he also commits adultery. It is a violation of God’s law on marriage and divorce and constitutes an adulterous relationship. Individuals who continue in this relationship are living in sin. Paul wrote to the brethren in Colosse: “Put to death therefore your members which are upon the earth: fornication, uncleanness, passion, evil desire, and covetousness. . . wherein ye also once walked, when ye lived in these things (emphasis added) (Col. 3:5-7).”
Let us observe that brethren seem to have less difficulty in understanding what the relationship is when two people divorce and remarry for an unscriptural reason after they became Christians, than they do about two people in that situation before they became Christians. Brother R. L. Whiteside commented: “It is argued that aliens may divorce for any cause, and remarry; and then all their sins, including their loose marriages, are forgiven when they obey the gospel . . . If their marriage was a sin, can’they repent of that sin and continue in it? If they were living in adultery, are we to be told that obedience, or rather a form of obedience, of the gospel changed adultery into a virtue? Where would such a theory lead? If a man steals a car, drives it to a meeting, and then goes through a form of obedience of the gospel would that act make his possession right in the sight of God?
“It is also argued that, as the alien is not in a covenant relationship with the Lord, the Lord takes no notice of what he does; and that, not being under the law, he violates no law. But if that sort of reasoning is true, what makes an alien a sinner at all? Shall we teach the alien, no matter what he does, he commits no sin? If he commits no sin, wherein is he a sinner, and why does he need a Savior, and how can he be baptized for the remission of sins?” (Gospel Advocate, July 18, 1935).
All sinful relationships must be repented of whether they exist among those out of the church or those in the church. There is no double standard. Repentance stands between Godly sorrow and reformation of life and applies to all. John the Baptist told the Pharisees and Sadducees coming to him to, “bring forth therefore fruit worthy of repentance” (Matt. 3:8). The fruit of repentance is seen in a changed life. The Jews on the day of Pentecost asked Peter and the other apostles, “brethren, what shall we do?” (Acts 2:37). Peter commanded them to repent and be baptized for the remission of their sins (v. 38). Their repentance is seen by their fruit (v. 41). In Acts 8:22, Simon, an erring child of God, was told to repent and pray. Whether one is a child of God or an alien, he must repent and repentance demands a turning away from sin, bringing forth fruit worthy of repentance. Any sinful relationship should be severed, including an adulterous marriage. Herod was living with Herodias, his brother Philip’s wife. John told him, “It is not lawful for you to have her” (Matt 14:4). It should be obvious to all as to what would be necessary for this sinful relationship to cease.
In Ezra 10:1-19 we are told of Israelites who had sinned by marrying foreign women. Concerning this, “Ezra prayed and made a confession, weeping and casting himself down before God” and “the people wept very sore” (v.1). They confessed their sins and said, “yet now there is hope for Israel concerning this” (v.2). Then they said, “Now therefore let us make a covenant with our God to put away all the wives, and such as are born to them . . . and let it be done according to God’s law (v.3).”
God’s law of pardon is equally strong for both the alien and the erring child of God. As repentance is required of the erring child of God, it is also required of the alien who comes to God. Repentance requires the dissolving of an adulterous relationship. Please consider: if an alien who has been baptized can continue in an adulterous relationship that began before his baptism because the blood of Christ has washed away his sins, why cannot the child of God continue in an adulterous relationship after he has repented and prayed?
The grace and mercy of God have not been considered in this treatise, not being in the realm of humans. How far God’s grace and mercy will be extended at the day of judgment, we do not know. It must reach a long way to include any of us. Man has no prerogative in this matter. Our responsibility is to teach the truth of God’s word. We must plead the law of God, and if there is any clemency, it belongs to God the great judge of all.