The psalmist echo the words of the Apostle Paul in Psalm 1:1 Blessed is the man that walketh not in the counsel of the ungodly, nor standeth in the way of sinners, nor sitteth in the seat of the scornful.

He tells them that he has written to them in a previous letter to have no association with that particular man who committed incest. The word “fornicator” comes from the verb “to sell” which is from the verb “to pass through or carry over” (particularly as merchants) and thence to sell, describing a whoremonger or male prostitute.He tells them to be careful of immoral people, do not keep close company with them (MacArthur).

The Apostle Paul encouraged the believers in Corinth to live a life befitting of Christ in them. He urged them not to return to the way of the old man (described here as the old leaven) nor to yield to the flesh (leaven of malice and wickedness. The word “malice” means to live a life characterised by an evil habit of the mind.

The Apostle Paul exposes the underlining problem of sin in the church in Corinth. He is saying to them to remember the finished work of Christ on the cross that delivered them from the bondage of sin. In grateful acknowledgement of their great deliverance, they are to live holy lives. Let their Christian witness be sincere and according to God’s Word. He renounced any hypocrisy or malice. He urged the Corinthian Christians to be true to their confession.

Barnes observed well, “The apostle here takes occasion, from the mention of leaven, to exhort the Corinthians to put away vice and sin. The figure is derived from the custom of the Jews in putting away leaven at the celebration of the passover. By the old leaven he means vice and sin; and also here the person who had committed the sin in their church. As the Jews, at the celebration of the passover, gave all diligence in removing leaven from their houses–searching every part of their dwellings with candles, that they might remove every particle of leavened bread from their habitations–so the apostle exhorts them to use all diligence to search out and remove all sin.”

The Apostle Paul has sensed that pride has overtaken the Corinthian Christians. He has observed that there is a false sense of spirituality built upon self-exaltation. In so doing, they have chosen not to deal with the sin that is in the camp. He warned that choosing not to see the corruption within the body will affect the wellbeing of the entire church.

The Apostle Paul is seeking to help this errant one in the church in Corinth to repent of his sin by advising the church to discipline such a one through separating him from the congregation of God’s people – “To deliver such an one unto Satan for the destruction of the flesh”. This phrase means to discipline through excommunication. This is what Jesus described in Matthew 18:17 as a final step of discipline to “let him be unto thee as an heathen or publican”, to treat him as an outsider of the church, to Satan’s world. He loses the encouragement and support of the brethren in the church!

The Apostle Paul urged the church in Corinth to be mindful of the power that delivered them from the bondage of sin – the power of our Lord Jesus Christ. Jesus broke the stronghold of sin on the cross where He alone bore our sins. And that power is not diminished. They have been freed from the bondage of sin through the gospel. Jesus died for our sins and rose victorious over sin on the third day by His resurrection from the dead.

The Apostle Paul is deeply concerned about the toleration of sin within the church in Corinth and he is urging the leadership of the church to take the step to discipline this errant brother. He tells them his assessment of this man’s spiritual state, as though he was present with them. He needs to be disciplined so that there is a restored order in the church, an intolerance for sin to fester.