1 Corinthians 5:7-8

Twentieth_Century(i) 7 Get rid entirely of the old leaven, so that you may be like new dough-free from leaven, as in truth you are. For our Passover Lamb is already sacrificed-Christ himself; 8 Therefore let us keep our festival, not with the leaven of former days, nor with the leaven of vice and wickedness, but with the unleavened bread of sincerity and truth.