The fact that a person has repented of his sins and claimed salvation in Christ does not mean that his whole character has been instantly transformed. Certainly, a vitally important process of change has been set in motion, but it may take many years for that change to be worked out in every area of his character.
When David needed smooth stones to fit in his sling so that he could slay Goliath, he went down to the valley—the lowly place of humility. There in the brook he found the kind of stones he needed. What had made them smooth? Two pressures: first, the water flow-ing over them; second, their continual jostling against one another.
This is a picture of how Christian character is formed. First, there is the continual washing of water by the Word (see Ephesians 5:26). Second, as we “jostle” one another in personal relationships, our rough edges are gradually worn down until they become smooth. We are “living stones” who need continual smoothing. (See 1 Peter 2:5.)
Let me add a side comment that when Jesus needs “living stones” for His sling, He, too, goes to the valley—the place of humili-ty. There, He chooses stones that have been made smooth by the ac-tion of God’s Word and by the pressures of regular fellowship with other believers. It is a mark of spiritual maturity to sincerely love our fellow Christians, not simply for what they are in themselves, but for what they mean to Jesus, who shed His lifeblood for each of them.