1 Corinthians 5:11
But now I have written unto you not to keep company, if any man that is called a brother be a fornicator, or covetous, or an idolater, or a railer, or a drunkard, or an extortioner; with such an one no not to eat. But now I have written unto you not to keep company, if any man that is called a brother be a fornicator, or covetous, or an idolater, or a railer, or a drunkard, or an extortioner; with such an one no not to eat.
The command belongs to a brief earlier letter in which Paul told the Corinthians he planned to visit them immediately after leaving Ephesus and again on his return from Macedonia, and in that same letter he commanded them to cease all communication with members who persisted in profligacy. It is part of his instruction for the church to confront and put away serious evil, including sexually immoral conduct that disgraces the church, meant to lead the members to repent and act before he visited them. The command is not to keep company, associate in ordinary fellowship, or even eat with anyone called a brother who persists in serious sin such as fornication, profligate, unchristian, or impure conduct.
That instruction was perverted, twisted, quibbled over, and argued about by some believers, who used their interpretation as an excuse to disregard it. Even in her best estate the church holds two classes, and those who willfully indulge in sin while professing to follow Christ are not to be received into the church. Faulty character or defects alone do not forbid connection, for such persons may join with Christ's followers to share his teachings and example and have opportunity to see their errors, repent, and by divine grace purify the soul in obeying the truth.
In the setting of the Lord's supper and communion, open persistent sin excludes the guilty person, and the church must not fellowship or share communion with such a one. The warning applies to seducers who disguise sin as holiness and to the sexually immoral, requiring Christians to shun them, not take them into the home, refuse them hospitality or approval, cut off association, and not listen to suggestions that defile the soul. Sin in the church must be addressed by first firmly showing those at fault their wrongs and requiring the erring member to forsake sin; if they do not reform, they are to be separated from the faithful so God's people remain clean and pure.
One who has knowingly rejected light and truth and placed himself beyond the church's reach cannot be fellowshiped, and censure must remain so the church's moral standard is not lowered. Even if he repents, his case is to be left alone and he must go without its sympathy or fellowship. The verse does not authorize people to judge who else may participate; beyond this clear case of open sin, each person is to examine himself or herself.
Those who cherish evil under a profession of godliness hate those who disturb their peace by condemning their sin, and when opportunity comes they betray those who sought to reprove them for their good, as Judas did. Secret cherishing of iniquity under profession, as with Ananias and Sapphira, calls forth the judgments of God to rid the church of the foul blot on its purity, striking terror to hypocrites so they cannot long remain with those who constantly represent Christ. Trial and persecution keep the church comparatively pure by leaving only those willing to forsake all for truth.