Arrogantly, many in the Corinthian church called into question not only the authority of the Apostle Paul and the wisdom of the cross (1 Cor. 5:1–2) but also the old covenant Scriptures. We see this in their toleration of a sexual relationship between a member of the church and his stepmother (1 Cor. 5:1; see Lev. 18:8). The solution, in light of the man’s presumed impenitence, is his excommunication or being cast out of the church (v. 2).
Paul gives the Corinthian church instructions on how to do this in today’s passage. First, he tells the church that he is present in spirit and has already made a prophetic judgment on the matter. He is probably responding to those who, as part of their questioning his authority, had been accusing him of abandoning them. Paul’s response to this is that although he had been absent in body, he had nonetheless been truly present with them. The idea here seems to be that because believers have been united to Christ by faith (see 1 Cor. 6:17), they are actually together, spiritually speaking, whenever the church gathers. Christ has said that He is present when the church gathers in His name (Matt. 18:20), and if we are truly made one with Him, there must be a sense that we are present wherever He is present even if not physically. This is confirmed by texts such as Hebrews 12:18–24, where we read that believers on earth enter the heavenly assembly of departed saints to worship the Lord. The only way this could happen is through our union with Christ by the Holy Spirit, which places us wherever Christ is, even if this presence is not discernible to our five senses.
Second, Paul says that he has made a prophetic judgment that the man should be excommunicated (1 Cor. 5:3). According to the standards of cutting off the sexually immoral in Israel (Lev. 18), Paul has exercised his Apostolic authority to excommunicate the man. So, when the church gathers in Paul’s physical absence, this excommunication is to be carried out, for the Apostle is there among them and they are present to affirm the decision (1 Cor. 5:4–5).
In excommunication, the church will be delivering the man to Satan for the destruction of his flesh (v. 5). God’s blessed domain is the church, and outside the church is the kingdom of darkness (see Col. 1:13–14). Effectively, the church will return the man to citizenship in the fallen world so that he will suffer outside God’s blessing, see his error, and return to Christ in repentance for his sin.