1 Corinthians 5:7-8

Thomson(i) 7 Purge out therefore the old leaven that you may be a new mass as you are unleavened. For Christ our Paschal lamb is indeed slain for us, 8 so that we should keep the festival, not with old leaven, nor with the leaven of wickedness and malignity; but with the unleavened bread of sincerity and truth.