1 Corinthians 5

1 Corinthians 5
5 It is actually reported that there is sexual immorality among you, and of a kind that even pagans do not tolerate: A man is sleeping with his father’s wife. ² And you are proud! Shouldn’t you rather have gone into mourning and have put out of your fellowship the man who has been doing this? ³ For my part, even though I am not physically present, I am with you in spirit. As one who is present with you in this way, I have already passed judgment in the name of our Lord Jesus on the one who has been doing this. ⁴ So when you are assembled and I am with you in spirit, and the power of our Lord Jesus is present, ⁵ hand this man over to Satan for the destruction of the flesh, so that his spirit may be saved on the day of the Lord.
There was incest happening in the church and Paul told them to expel the person.  Our society may cringe over Paul's use of "hand him over to Satan", but that is because our society has become so politically correct and we don't want to hurt anyone's feelings.  There was a song on the radio growing up that said, "I'm going to hell in a bucket, but at least I'm enjoying the ride.".  That's exactly what we tend to do.  We tollerate sin because we don't want to upset people.

⁶ Your boasting is not good. Don’t you know that a little yeast leavens the whole batch of dough? ⁷ Get rid of the old yeast, so that you may be a new unleavened batch—as you really are. For Christ, our Passover lamb, has been sacrificed. ⁸ Therefore let us keep the Festival, not with the old bread leavened with malice and wickedness, but with the unleavened bread of sincerity and truth.

"A little yeast leavens the whole batch." If we tolerate sin in our churches then others will sin because they see there is no immediate consequence.  Before one knows it, the church looks just like the world. Why would people want what we have if the only difference in our lives is that we lose sleep on Sunday while they sleep in?

⁹ I wrote to you in my letter not to associate with sexually immoral people— ¹⁰ not at all meaning the people of this world who are immoral, or the greedy and swindlers, or idolaters. In that case you would have to leave this world. ¹¹ But now I am writing to you that you must not associate with anyone who claims to be a brother or sister but is sexually immoral or greedy, an idolater or slanderer, a drunkard or swindler. Do not even eat with such people.
¹² What business is it of mine to judge those outside the church? Are you not to judge those inside? ¹³ God will judge those outside. “Expel the wicked person from among you.”

Notice that we are only to remove ourselves from the sexually immoral the claim to be brothers.  And we ARE to judge our brothers actions based on scripture.  Matthew 7:3-5  Matthew 18:15-17

Grace and peace to you from God our Father and the Lord Jesus Christ.