The following is an excerpt from The MacArthur New Testament Commentary on 1 Corinthians 5.

I have decided to deliver such a one to Satan for the destruction of his flesh, that his spirit may be saved in the day of the Lord Jesus. (5:5)To put the professed believer out of their fellowship, to excommunicate him, would be to deliver such a one to Satan for the destruction of his flesh. Satan is the ruler of this world, and turning a believer over to Satan, therefore, thrusts the believer back into the world on his own, apart from the care and support of Christian fellowship. That person has forfeited his right to participation in the church of Jesus Christ, which He intends to keep pure at all costs. The word deliver (paradidomi) is a strong term indicating the judicial act of sentencing, of handing over for punishment. The sentence passed on a sinning believer is to be given to Satan. Paul excommunicated Hymenaeus and Alexander because of their continued and unrepented blasphemy. They were pastors with a false gospel; he “delivered [them] over to Satan that they may be taught not to blaspheme” (1 Tim. 1:20).

The result of such discipline is the destruction of the flesh. Destruction (olethros) may refer even to death. It is used frequently in connection with divine judgment on sin. But Satan has no power over the spirits of believers. When Satan attacked Job, he was only allowed to harm that man of God physically. He could destroy his possessions and afflict his body, but he could not destroy his soul. The inner believer belongs entirely to Christ and we have the absolute assurance that he will be saved in the day of the Lord Jesus. But in the meanwhile the unrepentant believer may be turned over to suffer greatly at the hands’ of Satan.

Jesus made it clear that all suffering and affliction is not the direct result of sin—just as Job’s was not. When the disciples assumed that the man born blind was being punished because of sin, Jesus replied, “It was neither that this man sinned, nor his parents; but it was in order that the works of God might be displayed in him” (John 9:2–3). Scripture is just as clear, however, that sickness may be the direct result of sin. Because some of the Corinthian Christians had abused and unworthily participated in the Lord’s Supper, Paul told them, “For this reason many among you are weak and sick, and a number sleep” (1 Cor. 11:30). Physical weakness, sickness, and even death can result from persistent sinning. When Ananias and Saphira lied to the church about the proceeds from the sale of their property, they also lied to the Holy Spirit. Their wickedness caused them to die on the spot, “And great fear came upon the whole church, and upon all who heard of these things” (Acts 5:1–11). Because they were believers, the Lord took them to be with Himself, but He could not allow such wickedness to corrupt the church.

The destruction of the flesh indicates that the incestuous man in Corinth would eventually die unless he repented of his sin. We are not told of the specific affliction, disease, or circumstances, but his body was on the way to destruction in a special disciplinary way. If he kept sinning, his life would end before he otherwise would have died. He would go to heaven, if he was truly a believer; but he would go before he should have gone. To protect His church, the Lord would have to take him early. Since some believers hold so tightly to this life because they have such limited vision of heaven, such deadly discipline acts as a warning of what might happen to them because of sin.

Perhaps the man did repent. He may be the one spoken of in 2 Corinthians, whom Paul said should be forgiven and comforted and for whom they should reaffirm their love, “in order that no advantage be taken of us by Satan; for we are not ignorant of his schemes” (2:5–11). A disciplined brother is still a brother and is never to be despised, even when unrepentant (2 Thess. 3:14–15). And if he repents, he is to be forgiven and restored in love (Gal. 6:1–2).