1 Samuel 17:34-40

But David said to Saul, “Your servant has been tending his father’s sheep. When a lion or a bear came and carried off a lamb out of the flock, I went out after it, struck it down, and rescued the lamb out of its mouth. If it rose up against me, I grabbed him by its fur, struck it and killed it. Your servant has killed both the lion and the bear, so this uncircumcised Philistine will become like one of them—since he has defied the ranks of the living God.” Then David said, “ADONAI, who has delivered me from the paw of the lion and from the paw of the bear, will deliver me from the hand of this Philistine.” “Go!” said Saul to David, “and may ADONAI be with you.” Then Saul clothed David with his own garb, put a bronze helmet on his head, and clothed him in armor. David strapped his sword on his garment and tried to walk, but he was not used to it. So David said to Saul, “I cannot walk in these, for I am not used to them.” So David took them off. Then he took his staff in his hand, chose five smooth stones from the valley, put them in the pocket of the shepherd’s bag that he had, and with his sling in his hand, he approached the Philistine.