1 Corinthians 5:6-8
6aYour boasting is not good. bDo you not know that ca little leaven leavens the whole lump? 7Clean out the old leaven so that you may be a new lump, just as you are in fact unleavened. For Christ, our aPassover lamb, also was sacrificed. 8Therefore let us celebrate the feast, anot with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth.