1 Corinthians 5:6-7

Boasting over your tolerance of sin is inappropriate. Don’t you understand that even a small compromise with sin permeates the entire fellowship, just as a little leaven permeates a batch of dough? So remove every trace of your “leaven” of compromise with sin so that you might become new and pure again. For indeed, you are clean because Christ, our Passover Lamb, has been sacrificed for us.