1 Samuel 17:37-40

And David said, “The LORD who delivered me from the paw of the lion and from the paw of the bear, He will deliver me from the hand of this Philistine.” And Saul said to David, “Go, and may the LORD be with you.” Then Saul clothed David with his garments and put a bronze helmet on his head, and he clothed him with armor. David girded his sword over his armor and tried to walk, for he had not tested them. So David said to Saul, “I cannot go with these, for I have not tested them.” And David took them off. He took his stick in his hand and chose for himself five smooth stones from the brook, and put them in the shepherd’s bag which he had, even in his pouch, and his sling was in his hand; and he approached the Philistine.