Not to go out of the world
But the apostle does not forbid us to have any intercourse at all, even with the people who do not know God. For then, he says, you would have to go out of the world (1 Corinthians 5:10), which he could never advise them to do. But he adds, If any man who is called a brother, who professes himself a Christian, is a fornicator, or covetous, or an idolater, or a railer, or a drunkard, or an extortioner (1 Corinthians 5:11), now I have written to you not to keep company with him, with such a one, no, not to eat. This must necessarily imply that we break off all familiarity, all intimacy of acquaintance with them. Yet do not count him as an enemy, but admonish him as a brother (2 Thessalonians 3:15). The apostle plainly shows that even in such a case as this we are not to renounce all fellowship with him. So that here is no advice to separate wholly, even from wicked people. Yes, these very words teach us quite the contrary.
1771 text
But the apostle does not forbid us, to have any intercourse at all, even with the men that know not God. For then, says he, ye must needs go out of the world, which he could never advise them to do. But he subjoins, If any man that is called a brother, that professes himself a Christian, be a fornicator, or covetous, or an idolator, or a railer, or a drunkard, or an extortioner――Now I have written unto you not to keep company with him; with such an one, no not to eat. This must necessarily imply, that we break off all familiarity, all intimacy of acquaintance with them. Yet count him not, saith the apostle elsewhere as an enemy, but admonish him as a brother: plainly shewing, that even in such a case as this, we are not to renounce all fellowship with him: so that here is no advice, to separate wholly, even from wicked men. Yea, these very words teach us quite the contrary.