What does delivering unto Satan mean in 1 Cor. 5: 5 and 1 Tim. 1: 20, and what connection has this, if any, with “excommunication” today?
The church is the sphere where the Spirit of God has sway. The world is the sphere in which Satan operates. They are respectively called “within” and “without.” The church is composed of those who have been called out of the world. The discipline of the Lord is exercised in the church seeing that the believer will not be judged with the world (1 Cor. 11: 32). To “deliver unto Satan” is, in effect therefore, to put an individual outside the church into a sphere where Satan is permitted to have some power over him (1 Cor. 5:5) as he had with Job. In the two passages cited by the questioner the action was apostolic and, seeing there is not present with us today apostolic authority no one can claim to deliver to Satan now. But the principle involved abides. It is to “put away” evil persons. Excommunication, if carried out according to Scripture, is a most solemn thing: it is the action of the assembly which “puts away” a person from the midst, removing him from “within” and putting him “without” (see ch. 5, vv. 12, 13). In both cases cited, God permitted the evil to show itself in apostolic times in order that they might be dealt with apostolic authority and thus furnish the church with guiding principles for post-apostolic days. The power of Satan is limited and the design of the discipline was the destruction of that which brought in the sin – the flesh. It was disciplinary, corrective and salutary.