1 Samuel 17:32-36

32And David said to Saul, “Let no man’s heart fail on account of this Philistine. Your servant will go and fight him!”

33But Saul replied, “You cannot go out against this Philistine to fight him. You are just a boy, and he has been a warrior from his youth.”

34David replied, “Your servant has been tending his father’s sheep, and whenever a lion or a bear came and carried off a lamb from the flock, 35I went after it, struck it down, and delivered the lamb from its mouth. If it reared up against me, I would grab it by its fur, strike it down, and kill it. 36Your servant has killed lions and bears; this uncircumcised Philistine will be like one of them, for he has defied the armies of the living God.”