I have written. Or, “I write.” The Greek may be understood either way. “I have written” would refer to Paul’s previous letter (see on v. 9); “I write,” to his present letter. Several other wicked practices are included with fornication in the list of sins that exclude a person from free and intimate fellowship with the saints. Believers are to keep themselves entirely separate from any person professing to be a Christian who is guilty of such things. Those who cling to immoral ways, in spite of their knowledge that God condemns all impurity, are without excuse. There is no valid reason for believers to hold familiar association with them.
Covetous, or an idolater. See on v. 10.
Railer. Or, “reviler,” one who heaps abuse or reproach upon others. Christians who form the habit of using abusive language are to be excluded from fellowship with the church. The natural tendency to meet insult with insult, reproach with reproach, abuse with abuse, unkindness with unkindness, is directly opposed to the spirit of Christ, who, “when he was reviled, reviled not again” (1 Peter 2:23). Compare 1 Cor. 6:10; Eph. 4:31; 1 Tim. 6:4; James 1:26; 3:5, 6, 10, 14; 4:11; 1 Peter 3:8-10.
Drunkard. Drunkenness is one of the works of the flesh (Gal. 5:19, 21). See on Prov. 20:1.
Extortioner. See on v. 10.
Not to eat. A specific example of the more general prohibition of the earlier part of the verse. The prohibition includes social meals (cf. Gal. 2:12) as well as the Lord’s Supper (DA 656). Believers should do nothing that would give observers reason to believe that defiant transgressors of God’s law are recognized as Christian brothers in good standing (see 2 John 10, 11). The standard of truth and purity must be held high. This was particularly important in Corinth in Paul’s day. The enemies of Christianity accused believers of various forms of crime and vice. If it became known that Christians tolerated in their midst, or had close contact with, wicked and immoral persons, those accusations and reports would receive support and be considered reliable. Therefore it was necessary to withdraw completely from wickedly impenitent apostates and let it be known that the church had no connection with them. Only thus could the church be kept pure and free from the contaminating influence of apostate sinners who refused to repent and give up their wickedness.