6:1-11 Paul deals with the case of litigation between believers.
6:12-20 Paul deals with sexual
immorality again, this time in the context of their freedom.
The problem is that they are proud (v.2) and boasting (v.6), the two words used in chapters 1-4, describing the wrong results of their spiritual giftedness (4:7). They think that since they have received the Spirit who has lifted them above the merely earthly, "all things are lawful." (6:12)
The action must be effected in the context of the gathered assembly. When the Corinthians are assembled, the Spirit is understood to be present among them (3:16); and for Paul that means that he, too, is present among them by that same Spirit.
Alternative translation: "As for my part, even though not physically present, I am present with you in S/spirit, and as such I have already, by the authority of our Lord Jesus, pronounced sentence on the man who has perpetrated this deed; so that when you and my S/spirit are assembled together along with the power of the Lord Jesus..."
destruction of the "flesh" (similar usage in 1Ti 1:20): expulsion from the church, thus turning him back out into Satan's sphere; it does not mean physical death as v.11 about not associating with "such a man" implies no immediate death. It probably refers to the destruction of what was "carnal" in him as actual separation from the church may lead to his putting aside his sins so that he might once more join the community. The express purpose of the action is his redemption.
Jewish folk wisdom: "A little leaven leavens the whole batch of dough" (cf. Gal 5:9). What is in view is not "yeast" which was not plentiful in antiquity, and which in any case is fresh and wholesome. "Leaven" was different. It consisted of keeping back a "little" portion of last week's dough, allowing it to ferment then adding it to this week's dough. Because of the fementation process, which week after week increased the dangers of infection, the Israelites were commanded once a year to purge their homes of all leaven (Ex 12:14-20). In the NT, leaven is a symbol of the process by which an evil spreads and infects the whole community.
Paul's metaphor of "leaven" relates to the Feast of Unleavened Bread and the Passover. They are to get rid of the "old leaven", the incestuous man, so that they might become a people without such sin in their midst. He reminds them of what made them unleavened bread: the sacrifice of God's Passover Lamb. Through his death we have received forgiveness from the past and freedom for new life in Christ. This event is the grounds for ethical behaviour.
the prolonged seven-day festival, during which the Jews were forbidden to eat anything leavened. On the crucifixion of Christ, God's people are to keep an ongoing feast of the celebration of God's forgiveness by holy living. "malice and wickedness": synonyms, referring to every form of sin; "sincerity and truth": behaviour that is fully authentic
The only way Christians can be a viable alternative to the world is for them to be in the world, but not of it (Jn 17:15-16). "Greed" (called "idolatry" in Col 3:5) means more than covetousness but defrauding or taking advantage of someone else.
Sin lists: Ro 1:29-31; 1Co 5:10-11, 6:9-10; 2Co 12:20-21; Gal 5:19-21; Eph 5:3-5; Col 3:5,8; 1Ti 1:9-10; 2Ti 3:2-5; Titus 3:3 (Mk 7:21-22; 1Pe 2:1, 4:3; Rev 21:8, 22:15)
The incestuous man is to be excluded from Christian fellowship meals, including the Lord's Supper. It is possible that they are not even to carry on ordinary social intercourse with him although dissociation in 2Th 3:15 implies that private fellowship may still be allowed.