God’s law on marriage, as with all moral issues, applies to non-Christians as well as to Christians. Because someone doesn’t know God’s moral law on marriage, just as with other matters, does not release them from the obligations to keep it and consequences for breaking them.
Baptism does not alter a sinful condition. The question of the effectiveness of baptism to save the unrepentant is before us. There are two kinds of sins. The ones we committed in the past that are done and can’t be taken back, and the ones that are on-going. Because marriage is an on-going institution, then repenting of a sinful marriage isn’t as easy as saying ‘sorry’ because it requires stopping the sin.
Baptism is effective to wash away all sin except for the sin that is not repented of and put away. What I mean is that IF baptism made any marriage acceptable to God, then even a Christian, already baptized, could plead ignorance or weakness, and be baptized again and would be equally forgiven and allowed to stay in any marriage in which he finds himself. Baptism does not have this power.
It is clear that Jesus taught a hard teaching when discussing divorce, Matthew 19:9ff. The disciples said if its like this, its better not to marry, Mt 19:10. Jesus didn’t say they were wrong or misunderstanding the conclusion of His words, but Jesus instead doubled-down and said that some make themselves Eunuchs to enter heaven. So its very clear that Jesus was teaching something very hard and said that what God joined together, let no man separate. The hard teaching is why John was arrested and beheaded. In the Old Testament Ezra and Nehemiah dealt with Jews who were married to foreign women. They didn’t say for them to say ‘sorry’ and never do it again. Instead they had to repent by putting the wives away. In such situations, there is a need for the husbands to put away their wives, but there is no call to be unsupportive of the women and children. It is not unheard of in the Scriptures to forbid that some be or stay married.
When discussing this matter, people bring up the children of the unscriptural marriage. Though some marriages must be abandoned, decency would dictate a continued responsibility to support and participate in raising the children. While we are expressing our concern for the children, it’s more important that we teach the truth about marriage so that children in general are born into a two-parent home and that they are not abandoned by easy divorce.
Can we get around this difficult teaching by nullifying or erasing those previous marriages, so that the new one is the first one in the eyes of God? For Herod, it was a marriage though unscriptural. For the men who married foreign women in the days of Ezra and Nehemiah, they were marriages though they were unscriptural. For the woman at the well whom Jesus spoke to, she was married several times even though she was not a Christian and even if she was ignorant of God’s law. The Catholics have tried to allow that its not a marriage unless done ‘in the church’, thus they allow for remarriages suggesting that the sin of fornication was all that was committed since the priest did not perform the ceremony. God does not sanction multiple marriages even though He recognizes their occurance.
Here’s the long story short: its a hard teaching which very few religious groups bother to enforce. We do in the church of Christ. Its tough and painful, but we do. And despite the painfulness, its also a blessing because we encourage men and women to work harder on keeping their marriages intact and enduring. Our children are blessed because we encourage strong marriage. So this is the wisdom of God that we teach the truth on this matter even when we admit how difficult it is to teach.