The Danger of Ignoring Sin in the Church

1 Corinthians 5:6, “...Don’t you realize that this sin is like a little yeast that spreads through the whole batch of dough? NLT
Paul is saying that unchallenged sin will spread throughout the church, in the same way that yeast spreads throughout a batch of dough. As a rock that is thrown into a pond creates a ripple that affects the whole pond, so sin affects the whole church. As food coloring slowly but surely works its way through the whole glass of water, so sin works its way through the whole church.

Think of it this way. If an employer turns a blind eye to an employee arriving late for work, soon all the other workers will be coming in late too. But if a worker arrives late and is verbally reprimanded the first time, his pay in docked the second time, and he is fired the third time - that employer will help create a work culture where punctuality is valued. In the same way - confronting sin will help create a church culture where purity is valued. As it relates to the church...

• If someone contemplating adultery sees someone in the church committing adultery (without anyone objecting) he/she will be encouraged to do the same. 
• If a couple contemplating living together prior to marriage sees someone else in the church doing that very thing (without anyone objecting) that couple will be encouraged to do the same.

Confronting sin has a cleansing effect on the church, while condoning sin has a contaminating effect on the church.