Prayer

"The first (great human reason we ought to pray) is because of what prayer does to our character. Prayer is like a time exposure to God. Our souls function like photographic plates, and Christ's shining image is the light. The more we expose our lives to the white-hot sun of His righteous life (for, say, five, ten, fifteen, thirty minutes, or an hour a day), the more His image will be burned into our character - His love, His compassion, His truth, His integrity, His humility."

(from: Disciplines of a Godly Man by R. Kent Hughes p. 83, published by Crossway Books)