Here the apostle advises them to shun the company and converse of scandalous professors. Consider,
I. The advice itself: I wrote to you in a letter not to company with fornicators, Co1 5:9. Some think this was an epistle written to them before, which is lost. Yet we have lost nothing by it, the Christian revelation being entire in those books of scripture which have come down to us, which are all that were intended by God for the general use of Christians, or he could and would in his providence have preserved more of the writings of inspired men. Some think it is to be understood of this very epistle, that he had written this advice before he had full information of their whole case, but thought it needful now to be more particular. And therefore on this occasion he tells them that if any man called a brother, any one professing Christianity, and being a member of a Christian church, were a fornicator, or covetous, or an idolater, or a railer, that they should not keep company with him, nor so much as eat with such a one. They were to avoid all familiarity with him; they were to have no commerce with him; they were to have no commerce with him: but, that they might shame him, and bring him to repentance, must disclaim and shun him. Note, Christians are to avoid the familiar conversation of fellow-christians that are notoriously wicked, and under just censure for their flagitious practices. Such disgrace the Christian name. They may call themselves brethren in Christ, but they are not Christian brethren. They are only fit companions for the brethren in iniquity; and to such company they should be left, till they mend their ways and doings.
II. How he limits this advice. He does not forbid the Christians the like commerce with scandalously wicked heathens. He does not forbid their eating nor conversing with the fornicators of this world, etc. They know no better. They profess no better. The gods they serve, and the worship they render to many of them, countenance such wickedness. "You must needs go out of the world if you will have no conversation with such men. Your Gentile neighbours are generally vicious and profane; and it is impossible, as long as you are in the world, and have any worldly business to do, but you must fall into their company. This cannot be wholly avoided." Note, Christians may and ought to testify more respect to loose worldlings than to loose Christians. This seems a paradox. Why should we shun the company of a profane or loose Christian, rather than that of a profane or loose heathen?
III. The reason of this limitation is here assigned. It is impossible the one should be avoided. Christians must have gone out of the world to avoid the company of loose heathens. But this was impossible, as long as they had business in the world. While they are minding their duty, and doing their proper business, God can and will preserve them from contagion. Besides, they carry an antidote against the infection of their bad example, and are naturally upon their guard. They are apt to have a horror at their wicked practices. But the dread of sin wears off by familiar converse with wicked Christians. Our own safety and preservation are a reason of this difference. But, besides, heathens were such as Christians had nothing to do to judge and censure, and avoid upon a censure passed; for they are without (Co1 5:12), and must be left to God's judgment, Co1 5:13. But, as to members of the church, they are within, are professedly bound by the laws and rules of Christianity, and not only liable to the judgment of God, but to the censures of those who are set over them, and the fellow-members of the same body, when they transgress those rules. Every Christian is bound to judge them unfit for communion and familiar converse. They are to be punished, by having this mark of disgrace put upon them, that they may be shamed, and, if possible, reclaimed thereby: and the more because the sins of such much more dishonour God than the sins of the openly wicked and profane can do. The church therefore is obliged to clear herself from all confederacy with them, or connivance at them, and to bear testimony against their wicked practices. Note, Though the church has nothing to do with those without, it must endeavour to keep clear of the guilt and reproach of those within.
IV. How he applies the argument to the case before him: "Therefore put away from among yourselves that wicked person, Co1 5:13. Cast him out of your fellowship, and avoid his conversation."

For then must ye needs go out of the world - What an awful picture of the general corruption of manners does this exhibit! The Christians at Corinth could not transact the ordinary affairs of life with any others than with fornicators, covetous persons, extortioners, railers, drunkards, and idolaters, because there were none others in the place! How necessary was Christianity in that city!

Yet not altogether with the fornicators of this world,.... By "the fornicators of this world" are meant, such as were guilty of this sin, who were the men of the world, mere worldly carnal men, who were never called out of it, or ever professed to be; in distinction from those that were in the church, that had committed this iniquity; and the apostle's sense is, that his former prohibition of keeping company with fornicators was not to be understood as referring to such persons as were, out of the church, as if no sort of civil conversation and commerce were to be had with men of such, and the like infamous characters; or with the covetous, or extortioners, or with idolaters: that is, of this world; for this clause is to be understood of each of these; so we read (n) of , "the covetous of the world"; by the covetous are meant, either such who are given up to inordinate lusts, who work all uncleanness with greediness, and can never be satisfied with their filthy enjoyments; or such who are greedily desirous of riches and wealth, and of increasing their worldly substance by any method, right or wrong; and who not only withhold that which is meet from others, but will not allow themselves what is proper and necessary: "extortioners" are either "ravishers", as the word may be rendered: such who by force violate the chastity of others, youths or virgins; or robbers, who, by violence and rapine, take away that which is the fight and property of others; or such who oppress the poor, detain their wages by fraud, or lessen them, and extort that by unlawful gain, which is unreasonable: idolaters are those who worship the false deities of the Heathens, or any idol, graven image, or picture of God, or men, or any creature whatsoever, or any but the one Lord God. The apostle, under these characters, comprises all manner of sin against a man's self, against his neighbour, and against God; against himself, as fornication; against his neighbour, as covetousness and extortion; and against God, as idolatry: and since the world abounded with men guilty of these several vices, all kind of civil correspondence with them could not be avoided,

for then must you needs go out of the world; meaning not out of Greece, or of any of the cities thereof, into other parts, but out of the world itself; they must even destroy themselves, or seek out for a new world: it is an hyperbolical way of speaking, showing that the thing is impracticable and impossible, since men of this sort are everywhere; and were all trade and conversation with them to be forbidden, the families of God's people could never be supported, nor the interest of religion maintained; a stop would soon be put to worldly business, and saints would have little or nothing to do in the world; wherefore, as the Arabic version reads it, "business would compel you to go out of the world".

(n) Zohar in Exod. fol. 31. 2.

Limitation of the prohibition alluded to in Co1 5:9. As in dissolute Corinth to "company with no fornicators," &c., would be almost to company with none in the (unbelieving) world; ye need not utterly ("altogether") forego intercourse with fornicators, &c., of the unbelieving world (compare Co1 10:27; Joh 17:15; Jo1 5:18-19). As "fornicators" sin against themselves, so "extortioners" against their neighbors, and "idolaters" against God. The attempt to get "out of the world," in violation of God's will that believers should remain in it but keep themselves from its evil, led to monasticism and its consequent evils.