2 Corinthians 2:4

For out of much affliction and anguish of heart I wrote unto you with many tears; not that ye should be made sorry, but that ye might know the love which I have more abundantly unto you.

This continues to be a reference to 1Corinthians, nor can this be construed as any sort of proof of a second lost letter between the canonical Corinthians. The notion that 1Corinthians could not have been written out of "anguish of heart" betrays a total insensitivity to the things which most assuredly can cause anguish of heart to any Christian, especially to the apostle who had converted them and had such love for them. The conditions at Corinth, described in 1Corinthians, were exceedingly deplorable. Incest, heartless lawsuits by the members before pagan judges, drunkenness at the Lord's table, arrogant self-seeking among the members, denials of the resurrection, warring, loveless factions, etc., etc. "Any one of these things was sufficient to cause Paul real distress and the severest grief."[9] McGarvey also understood this verse as a reference to 1Corinthians.