Right now I am going through a situation with my daughter. She got a divorce a few months ago and she has found a new man. He has teenage children. My daughter has two children 10 and 8; great kids, of course. My daughter is a great kid but making bad decisions. She has decided to allow this man to move in with her and the girls. I do not know about his children, she did indicate that he has custody of his children and they do live with Him. By the way, he is a former youth pastor; imagine that!
I have decided to not socialize with them as much as I could. I have not met him; probably there is something in the mix for the holidays, but I probably will not attend. My parents have passed away; my mother just last year. I have a married sister, so it would be just us, my wife and I with them at dinner. I am afraid I might say something out of line. I have already told her that it is wrong. She knows that, but indicates that "her mother lived with a man and it didn't do anything to hurt her." This was after my former wife and I divorced.
Complicated, huh? I have tried to simplify it somewhat here. I sometimes choose to take the hard-line, but it has gotten me into trouble more than once. I am all ears for your comments
Most sins have ramifications far beyond what we initially expect. Yes, the relationship is complex, but I have seen worse; though that doesn't make yours any better.
There are times when hardstands are needed. Many people won't believe you mean something until you make a stand. However, hardstands will have hard consequences. Recall what happened to John the Baptist. He told the ruler of his country, "It is not lawful for you to have your brother's wife" (Mark 6:18). He ended up losing his head over the matter (Mark 6:27-28). Does that mean John shouldn't have said anything? No, actually quite the opposite. Somebody had to take a stand for the truth. But we have to expect that those uninterested in the truth will strike back. "The desire of the righteous is only good, but the expectation of the wicked is wrath" (Proverbs 11:23).
God warned, "He who justifies the wicked, and he who condemns the just, Both of them alike are an abomination to the LORD" (Proverbs 17:15). We must be careful that by our actions (or inactions) we do not leave an impression that we approve of a person's sin (Romans 1:32). This is why Paul told the Corinthians, "I wrote to you in my epistle not to keep company with sexually immoral people. Yet I certainly did not mean with the sexually immoral people of this world, or with the covetous, or extortioners, or idolaters, since then you would need to go out of the world. But now I have written to you not to keep company with anyone named a brother, who is sexually immoral, or covetous, or an idolater, or a reviler, or a drunkard, or an extortioner--not even to eat with such a person" (I Corinthians 5:9-11). When a person pretends to be a Christian living a godly life and yet is wallowing in sin, the proper course of action is to cut off all social contact because the person will conclude that you think they are fine as they are.
There will most likely be consequences to that stand. You might not see your granddaughters for a long while. Still, choices must be made. "If anyone comes to Me and does not hate his father and mother, wife and children, brothers and sisters, yes, and his own life also, he cannot be My disciple. And whoever does not bear his cross and come after Me cannot be My disciple" (Luke 14:26-27).
I would suggest letting your daughter know that you love both her and her children. Because of that love, you do not want to see any of them harmed, and yet she is snubbing her nose at her Creator (see "Why Sex Outside of Marriage is Wrong" and "Waiting for the Proper Time"). She is increasing the odds that her daughters will be in danger, either from her live-in stud or his teenage children. There is a growing body of evidence that live-in arrangements increase the odds of harm to children (see "Should We Live Together?" from the National Marriage Project). The fact that her stud was a former minister doesn't make the situation better -- it makes it worse because here is a man who knows the teaching of God and he has purposely gone against God. "For if we sin willfully after we have received the knowledge of the truth, there no longer remains a sacrifice for sins, but a certain fearful expectation of judgment, and fiery indignation which will devour the adversaries" (Hebrews 10:26-27). If God cannot restrain his actions, then he has no restraint on anything he decides to do since he has no moral foundation. Therefore, until she rectifies the situation, she will receive no support from you: monetary or social.
It is sad to see how your ex-wife's sin has become a justification for your daughter's sin. The flaw in her reasoning is that one person's sin doesn't make another's right. It still remains sinful. Worse, your granddaughters will most likely follow their mother's leading. The odds are that they won't even bother getting married and most likely will be having sex in their later teenage years. When your daughter objects, they will throw her own behavior right back in her face as justification for their own.
No yelling, no screaming, just a quiet but firm "here is how it is going to be." And a lot of prayers that she returns to God for lasting damage is done.