1 Corinthians 5:6-8

"Your boasting is not good. Don't you know that a little yeast works through the whole batch of dough? Get rid of the old yeast that you may be a new batch without yeast - as you really are. For Christ, our Passover lamb, has been sacrificed. Therefore let us keep the Festival, not with the old yeast, the yeast of malice and wickedness, but with bread without yeast, the bread of sincerity and truth."

These is a BIG problem

with old yeast!

I am sure your grandmothers told you about how yeast works! It makes the bread dough rise. A little bit affects the whole batch. So it is in our church families, a little bit of blatant sin, uncorrected, affects the whole congregation. Believers should encourage, pray for, and build up one another, they must also be intolerant of sin that jeopardizes the spiritual health of the church.