1 Corinthians 5:6-8

6Your boasting about this is terrible. Don’t you realize that this sin is like a little yeast that spreads through the whole batch of dough?

7Get rid of the old “yeast” by removing this wicked person from among you. Then you will be like a fresh batch of dough made without yeast, which is what you really are. Christ, our Passover Lamb, has been sacrificed for us.

8So let us celebrate the festival, not with the old bread of wickedness and evil, but with the new bread of sincerity and truth.