1 Corinthians 5:6

“Your vaunt is not good:” καύχημα, materies gloriandi (cf. αἰσχρὸν κλέος, Eurip., Helena, 135: Mr [834]), found in the state of the Church, of which the Cor [835] were proud (1 Corinthians 4:6 ff.) when they ought to have been ashamed. καλόν, good in the sense of seemly, of fine quality; cf. 2 Corinthians 8:21; John 10:32, etc. For οὐκ οἴδατε …; see 1 Corinthians 3:16. The Cor [836] might reply that the offence, however shameful, was the sin of one man and therefore a little thing; P. retorts, that it is “a little leaven,” enough to “leaven the whole kneading”: cf. the Parables of Matthew 13:33 and Luke 12:1. A sin so virulent held an indefinite power of corruption; it tainted the entire community. The φύραμα (φυράω, to mix) is the lump of dough kneaded for a single batch of bread: see parls.

[834] Meyer's Critical and Exegetical Commentary (Eng. Trans.).

[835] Corinth, Corinthian or Corinthians.

[836] Corinth, Corinthian or Corinthians.