1 Corinthians 5:6-8

5:6 Your boasting is not good. Don’t you know that a little yeast affects the whole batch of dough? 5:7 Clean out the old yeast so that you may be a new batch of dough – you are, in fact, without yeast. For Christ, our Passover lamb, has been sacrificed. 5:8 So then, let us celebrate the festival, not with the old yeast, the yeast of vice and evil, but with the bread without yeast, the bread of sincerity and truth.