1 Corinthians 5:6–8
6 fYour boasting is not good. Do you not know that ga little leaven leavens the whole lump? 7 Cleanse out the old leaven that you may be a new lump, as you really are unleavened. For Christ, our Passover lamb, has been sacrificed. 8 Let us therefore celebrate the festival, hnot with the old leaven, ithe leaven of malice and evil, but with the unleavened bread of sincerity and truth.
Galatians 5:9
9 jA little leaven leavens the whole lump.