1 CORINTHIANS 5:9-10
"I told you not to associate with people who indulge in sexual sin. But, I was not talking about unbelievers who indulge in sexual sin, or are greedy, or cheat people or worship idols. YOU WOULD HAVE TO LEAVE THIS WORLD to avoid people like that."
The clear message here is that we are not to associate with anyone who claims to be a believer but still indulges in sexual sin, is abusive, a drunkard or a cheat and is greedy and worships idols. In fact we are not even to eat with such people. So what is the distinction to be made here? Unbelievers are not the point of the message here. Unbelievers by definition do not fear God and will do anything they can think of. No Paul is talking here about those who profess to know, love and follow Jesus Christ and fear God, but commit the same sins as unbelievers!
Paul did not mean to never associate with unbelievers. Paul means to not associate closely or habitually with the unchaste or impure. Paul does not mean we should shun the immoral people of this world as he knows that it is impossible. In fact he points our that we would have to leave this world to avoid people like those unbelievers and so called believers that commit the same sins. By the same token, Paul advises that we do associate with true believers that can be seen by their fruit.
How about you? Who do you associate with? Who do you spend your time with on a regular basis? If those you associate with continue to indulge in sexual sin, greed, drunkenness, or worship other gods on a habitual basis, they are not true believers and they will be know to you by their actions and their fruit. We are to make judgements, sometimes with appropriate counsel and then to take action. You always make choices, one at a time, and you are responsible for your decisions. You have a choice who to be with and associate with. We are pilgrims passing through this world and we will be known in part by our friends and associates. To avoid sin and sinful people YOU WOULD HAVE TO LEAVE THIS WORLD. Thank God we will be saved.
