A sponge is used for cleaning dishes or even for washing a car. When a sponge is dry, it becomes hard and often loses its utility—especially in the case of washing a vehicle! When a sponge is damp, however, it becomes malleable, much more useful, and reaches its full potential. Believers should be like a damp sponge when it comes to the gospel, soaking in and absorbing all its truth and richness so they can be a useful tool for the kingdom.