I Corinthians 5:1-6, 11-13

It is actually reported that there is sexual immorality among you, and such sexual immorality as is not even named among the Gentiles—that a man has his father’s wife! And you are puffed up, and have not rather mourned, that he who has done this deed might be taken away from among you. For I indeed, as absent in body but present in spirit, have already judged (as though I were present) him who has so done this deed. In the name of our Lord Jesus Christ, when you are gathered together, along with my spirit, with the power of our Lord Jesus Christ, deliver such a one to Satan for the destruction of the flesh, that his spirit may be saved in the day of the Lord Jesus. Your glorying is not good. Do you not know that a little leaven leavens the whole lump?

But now I have written to you not to keep company with anyone named a brother, who is sexually immoral, or covetous, or an idolater, or a reviler, or a drunkard, or an extortioner—not even to eat with such a person. For what have I to do with judging those also who are outside? Do you not judge those who are inside? But those who are outside God judges. Therefore “put away from yourselves the evil person.”