1 Corinthians 5:6-8 New American Standard Bible (NASB)
6 Your boasting is not good. Do you not know that a little leaven leavens the whole lump of dough? 7 Clean out the old leaven so that you may be a new lump, just as you are in fact unleavened. For Christ our Passover also has been sacrificed. 8 Therefore let us celebrate the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth.