There is a kind of worldling with whom believers can associate and another kind with whom we must not. We can appreciate all true image-bearing contributions from unbelievers and we can associate with them while recognizing their sinfulness. Paul’s instruction to the Corinthians is clear on the matter.
I wrote to you in my letter not to associate with sexually immoral people—-not at all meaning the sexually immoral of this world, or the greedy and swindlers, or idolaters, since then you would need to go out of the world. (1 Corinthians 5:9–10)
Unbelievers sin, they can’t help but sin, and we can still associate and mingle with them. That is, we can buy from and sell to, live next to, work with, and enjoy some of life with them. We can associate with non-Christians on the basis of common grace while proclaiming to them their need for redeeming grace.
But we must not associate with those who profess to be believing brothers, who claim to share redeeming grace but who give no evidence of redemption from sin.
But now I am writing to you not to associate with anyone who bears the name of brother if he is guilty of sexual immorality or greed, or is an idolater, reviler, drunkard, or swindler—not even to eat with such a one. (1 Corinthians 5:11)
We have different levels of association because we share different things in common with different people. Often our expectations reverse God’s Word. We disassociate with the world because they won’t act right while we continue to associate with any so-called Christian in the name of grace. This is our failure to understand the different types of communion God gives. We share likeness with all men, we share salvation with believers. Our time around the Lord’s Table means something because we have Christ, not because we have an appetite.