1 Corinthians 5:6

οὐ καλὸν τὸ καύχημα ὑμῶν. That state of things of which you glory is not good. καύχημα properly signifies that whereof a man glories, and is so translated in Romans 4:2. Cf. ch. 1 Corinthians 9:15-16; 2 Corinthians 1:14; 2 Corinthians 5:12; 2 Corinthians 9:3, &c., where the same word is used, but is variously translated in our version. It is impossible always to insist on its strict sense. It is very frequently equivalent to καύχησις. The Corinthians are once more reminded how little cause they had for self-glorification. As long as they permitted such an offender to defile their society they were in a measure partakers of his sin.

μικρὰ ζύμη ὅλον τὸ φύραμα ζυμοῖ. The presence of a very small amount of evil in the Christian society imparts a character to the whole—a truth only too fully exemplified in the after-history of the Christian Church. From the evil that has crept into the Christian society men have taken occasion to deny its divine origin. The student of history will remember how dexterously Gibbon contrives to throw discredit upon Christianity by enlarging upon the shortcomings of the early Church, and by evading the comparison between its moral elevation and the shocking demoralization of heathen society. The same words are to be found in Galatians 5:9. φύραμα signifies a mass of dough, from φύρω to mix.