The Biblical Treatment of the Church and the World
Paul was once followed around for some days by a medium who called out the seemingly approving message that they spoke for God and told of salvation. This grieved Paul. He cast the spirit out of her and left her to go back to her paymasters. They weren't happy about it. See Acts 16:16 and following.
Compare Paul's behavior with these modern congregations that try to win people to Christ by being forever polite to them! Paul only cast the spirit out of the girl because he couldn't take her - in modern standards, very polite and agreeable - messing with him for days on end. And what did he do? Did he get her into a 12-steps program?! No. He dealt with the problem and left her. She obviously already knew about the doctrine of salvation he was spreading, so there was nothing more to say to her. It led to problems for Paul from the city rulers, who had him and his follow soldier for Christ, Silas, beaten and put in prison, which situation God used Paul to get the message of salvation to the jailer! And on it goes, with the girl left in the dust, and the real salvation message continuing on. She didn't hinder Paul's purpose for God in spreading the message of salvation, even though she helpfully told everyone what he was doing and falsely associated herself with him and with the Most High God's message of salvation.
Paul's behavior was for God, and he wasn't subverted from his purpose by the lost cause of stopping to talk the girl into salvation. We must use God's dividing line between Church and World, which is salvation doctrine, and wake up to the reality that the World is laughing at our attempts to force them with schemes to act like Christians even though they aren't and won't be Christians. Don't make friends with the World, because, as the Bible tells us, doing so is the same thing as being God's enemy! The vast majority of so-called churches that I know about are either actively engaged in this evil behavior or are extremely tepid and fearful about pointing out God's dividing line between Church and World. I think they'd feel better if they gave up their 501c3 status, which binds them to the rules of the World in their mission for God. I think they'd feel better if they saw the different ways that the Bible mandates for behaving toward the Church and the World - the World cannot keep from sinning, so we can freely associate with them, but the unrepentant sibling in Christ must eventually, by a process, be shunned for their own sake, and - get this - explicitly shunned for the purpose that Satan would abuse their bodies! That answers the old hand-wringing problem of whether or not to kick 25 year-old Johnny out of the house or to support uncle John's booze habit, if Johnny and John both claim to be Christians according to the Scriptures' description of the gospel Paul preached. We behave differently in many little ways to each other than the World has devised - and has taught us - to treat itself, with many little rules of conduct that don't naturally apply to us and which we should not take on ourselves or hold other Christians to. We develop in trust that is based on each individual abiding in Christ.