51 It is actually reported that there is immorality among you, and of a kind that is not found even among pagans; for a man is living with his father's wife. 2 And you are arrogant! Ought you not rather to mourn? Let him who has done this be removed from among you. 3 For though absent in body I am present in spirit, and as if present, I have already pronounced judgment 4 in the name of the Lord Jesus on the man who has done such a thing. When you are assembled, and my spirit is present, with the power of our Lord Jesus, 5 you are to deliver this man to Satan for the destruction of the flesh, that his spirit may be saved in the day of the Lord Jesus. 6 Your boasting is not good. Do you not know that a little leaven leavens the whole lump?
Matthew Henry's Commentary on 1 Corinthians 5:1-6
Commentary on 1 Corinthians 5:1-8
(Read 1 Corinthians 5:1-8)
The apostle notices a flagrant abuse, winked at by the Corinthians. Party spirit, and a false notion of Christian liberty, seem to have saved the offender from censure. Grievous indeed is it that crimes should sometimes be committed by professors of the gospel, of which even heathens would be ashamed. Spiritual pride and false doctrines tend to bring in, and to spread such scandals. How dreadful the effects of sin! The devil reigns where Christ does not. And a man is in his kingdom, and under his power, when not in Christ. The bad example of a man of influence is very mischievous; it spreads far and wide. Corrupt principles and examples, if not corrected, would hurt the whole church. Believers must have new hearts, and lead new lives. Their common conversation and religious deeds must be holy. So far is the sacrifice of Christ our Passover for us, from rendering personal and public holiness unnecessary, that it furnishes powerful reasons and motives for it. Without holiness we can neither live by faith in him, nor join in his ordinances with comfort and profit.