1 Corinthians 5:6-8

6You should not be so proud of yourselves. Think about what yeast does in bread. A very small amount of yeast changes the whole loaf of bread.

7The yeast in the flour is like one person who does wrong things. You must remove this old yeast from among you. Then you will be like a new loaf of bread. You are really like a loaf which has no yeast in it. You are pure, because Christ died as a sacrifice on our behalf. He is like the lamb that the Israelites killed for their Passover meal.

8As a result, we can have our own Passover festival. We must remove everything that is bad from among us. That is like what the Israelites did when they removed all the old yeast from their homes. Instead we live in a way that is pure and honest. It is like we are eating bread which has no yeast in it.