John Calvin Reformed @genevareformer

9. I wrote to you in an epistle. The epistle of which he speaks is not at this day extant. Nor is there any doubt that many others are lost. It is enough, however, that those have been preserved to us which the Lord foresaw would suffice.

Matthew Henry Presbyterian @wholebiblehenry

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.

Commenting on 1 Corinthians 5:9-13

John Gill Reformed Baptist @doctorgill

I wrote unto you in an epistle,..... Not in this same epistle, and in Co1 5:2 as some think; for what is here observed is not written in either of those verses, but in some other epistle he had sent them before, as is clear from Co1 5:11 which either came not to hand, or else was neglected by them; and so what he here...