Matthew Mitchell explains how he uses a simple object lesson to illustrate "the principle of overflow," which simply means that our words overflow from what's already in our hearts.

I held up a bottle of water and then poured the water out on the platform. Then I asked our church family, "Why is there now water on the floor?" Everyone laughed nervously because the answer was so obvious.

Then I asked, "But why is there water on the floor and not Pepsi or Kool-Aid?" Now besides the fact that I would have gotten into major trouble with the custodian if I had poured Pepsi or Kool-Aid on the carpet, the truth is, there was water on the floor because there had been water in the bottle. Similarly, Jesus said, "Out of the overflow of the heart the mouth speaks." What's inside us determines what comes out of us.