Why is it wrong for an unmarried couple to live together?

When I get asked this questions and I respond “because sex outside of marriage goes against God’s commands,” they would tell me that they’re not talking about that. They’re talking about co-habitation but without sexual immorality.

Suppose it really was the case that two people in a romantic relationship can really have the God-given self-control not to cross that line, would it still be a sin to live together? That’s the question, they say.

I think before we even answer that question, I would like to draw attention to the fact that this type of line-drawing is problematic. Some have this underlying assumption that “as long as I don’t cross that line, I’m good” as if Christianity was about following dos and don’ts and making sure to check the right boxes.

“Is it a sin?” is usually a red flag that shows we’re falling back into legalistic religion rather than a living relationship.

No cursing? Check.

No porn? Check.

Not getting drunk? Check.

This is as if to be married to someone was just making sure you buy flowers every so often, and to say “I love you” at just the right frequency and to not cheat. When someone asks “is it a sin,” it usually reveals the type of relationship that person has with God. Perhaps, there are more significant and deeper issues that should be dealt with than the question sticking out of the water.

If we really have realized the depth to which we are loved by God and have been forgiven despite our sin, we no longer do the bare minimum, and no longer seek to get as close to the line as possible without crossing it. Rather we seek to do our best to display our gratitude to God in everything that we do.

So is it wrong to co-habitate?

When one falls in love with God, God’s Spirit is in a person and convicts that person what is right and wrong. If a Christian already feels something wrong about cohabitation, or if that person attempts to hide it from the church, then that’s already a sign that that person believes it is wrong to cohabitate.

Of course, the wise thing to do is to stay away from situations that can cause sin. Cohabitation presents constant opportunities for secret sins to occur, sins that can slowly eat into a person’s conscience and weaken their faith, infecting other aspects of life.

And finally, to the eyes of the church, it is not unreasonable to assume that the couple is living in sexual immorality. Cohabitation can cause other believers to stumble and cause controversy in the church. Both of these things are serious sins that the couple is accountable to God for.

Now if the couple in question are new believers, then the church should show grace to them, like Christ showed grace to the woman at the well (John 4). The church can then counsel that couple to marriage so that their arrangement can be right before God and before the church.