What should Christian relationships with non-Christians look like?

I, like you, have friends and families who do not live Christian lifestyles. I have non-Christian neighbors. Here in secular New England, interactions with non-Christians seem inevitable. But, even when I lived in Bible-belt-ish Indiana, I would interact with many who were not Christians and many more whose life did not reflect the gospel whatever they called themselves. How should we, as Christians, relate to the person who does not live, well, like a Christian?

Christians are perennially confused about this question. Some strictly segment and separate themselves from non-believers, living a life solely within Christian cultures and communities. On the other hand, some live so tightly intertwined with other Christians that they are nearly inseparable. They have put up no walls between them and the world.

First, Christian relationships with unbelievers are inevitable. When addressing a scandalous relationship between a Christian and his stepmother, Paul exhorted the Corinthian Church to remove him from their fellowship (1 Cor 5:1–8). They must not “associate” with those who call themselves a brother but are engaged with unrepentant, serial sin (1 Cor 5:9–10). On the other hand, Paul clarifies, he is not speaking of those who are “of this world.” If that were the case “then you would need to go out of the world” (1 Cor 5:10). Paul indicates that he expects the Corinthians will remain in the world. Paul’s words would seem to keep us from either end of the spectrum mentioned above. Christians should be “in the world” but they ought not be “of the world.” A strict separationism is untenable, but so is a naked intermixing.

Second, the Bible is clear that Christians should be proactive in making and maintaining close friendships and relationships with other Christians. This is, in part, because Christians should not surround themselves with fools. “Whoever walks with the wise becomes wise, but the companion of fools will suffer harm,” (Prov 13:20). It is difficult to see how someone could love God but not love other Christians in a particular way. “Whoever loves God must also love his brother” (1 John 4:21).

Third, our Christian obligations and responsibilities take precedence over our relationships with the world. For example, Christians sometimes justify putting their kids in public schools by wanting them to be a witness to unbelieving kids. There might be good reasons to put your kids in public schools (resources, opportunities, sports); different families have different needs, and different schools have different strengths and weaknesses. But Christians have more of a responsibility to serve family than community, and this might entail finding different educational approaches. We are more responsible to our Christian community than other local communities. This might seem exclusivistic, but it is actually a witness to the world that we take our faith seriously.

Fourth, do not condone evil. As Christians, we must speak the truth. This includes calling evil what it is (Eph 5:12–13). This should, certainly, be seasoned with grace and kindness (1 Pet 3:14–16). We should be mindful about the words we say to our friends who are living in an unbiblical lifestyle. This does not mean we should not have friendships with them, but it does mean we should not let them think we approve of their lifestyles. This might be surprising and off-putting, but it should also be freeing. It is okay to say to a child who has gone astray or to a friend living in a way you disagree with, “I love you, but I disagree.”

Tolerance, the notion that we must accept the way everyone is or decides to live uncritically, is overrated. There is no way to grow or mature if you cannot receive criticism. There is no way to fix where you might be deficient if you cannot hear someone’s disagreement with you. And there is no way to have a completely open and honest relationship with someone if you cannot speak your mind. Simply put, if you try to live by uncritically “tolerating” anyone, you will not make it through life with many true friendships.

Fifth, Christians must not be partners in evil. Ephesians 5:11 tells us to “take no part in the unfruitful works of darkness.” Christians must not be partners in evil. But what does this word “partner” mean? This is the Greek word sugkoinoneo (συγκοινωνεω). The same or similar words are used elsewhere to describe Jesus’ relationship with his people (Rom 11:17), Paul’s relationships with his converts (1 Cor 9:23; Phil 1:7), the Philippians’ financial gift to Paul (Phil 4:14), John’s relationship with his reader (Rev 1:9), and joining in with sin the sins and consequent punishments of unbelievers (Rev 18:4). While these instances indicate relationships with greater and lesser degrees of intimacy, the word that would unite all these uses of the word is “covenant.” What I believe Paul is meaning to say is that Christians should not enter into covenant relationships with those committing the “unfruitful works of darkness.”

What counts as a covenant relationship? I would define a covenant relationship as an enduring relationship with obligations. Even this, however, is hard to pin down at times. There are certain relationships with are obviously covenantal such as marriage (Mal 2:10–16) and church membership (Acts 2:42). But, what about roommates? What about business partners? What about a doctoral candidate’s relationship with their supervisor? I would say wisdom should dictate how we handle these relationships and charity should govern how we relate to other Christians who might decide differently on those matters.

Another question which might arise is how we should handle pre-existing covenantal relationships. For example, Malachi 2:10 implies covenantal relationships between children and parents. What happens if a child strays from the faith, does the parent still have covenant obligations to them? What if an adult child becomes a christian, do they still have covenantal obligations to their parents? What if a spouse loses their faith? Do covenantal obligations remain in place? The Bible seems to indicate that when we enter into these kinds of covenantal relationships with others, we should keep these obligations to the best of our abilities, even if the other party does not.

This is one of the ways that we trust that God is the guarantor of all human relationships. God will, one day, judge what is evil. He will reward what is good. He will see the ways in which his people keep their covenants and he will reward them for this, even if the other party has not kept up their obligations.