For this cause many are weak and sickly
Because of their unworthy participation of the Lord's supper, many in the Corinthian church were attended with bodily infirmities and diseases; either by way of fatherly chastisement and correction in such who were truly the Lord's people, though they had behaved unworthily; or by way of punishment to such who were not, and had sinned very grossly:
and many sleep;
that is, die a corporeal death, which is often in Scripture signified by sleep, and frequently used of the saints, and their death, and may intend and include some of them here; for though the Lord might resent so far their unworthy conduct and behaviour at his table, as to remove them out of this world by death, yet their souls may be saved in the day of the Lord Jesus.