Purge out therefore the old leaven, that you may be a new lump, as you are unleavened. For even Christ our passover is sacrificed for us:
All Commentaries on 1 Corinthians 5:7 Go To 1 Corinthians 5
John Chrysostom
AD 407
Paul is not referring to this man only but to others as well. The old leaven is not just fornication but sin of every kind, which must be rooted out if the lump is to be pure.
