1 Samuel 17:33-35

17:33 But Saul replied to David, “You aren’t able to go against this Philistine and fight him! You’re just a boy! He has been a warrior from his youth!”

17:34 David replied to Saul, “Your servant has been a shepherd for his father’s flock. Whenever a lion or bear would come and carry off a sheep from the flock, 17:35 I would go out after it, strike it down, and rescue the sheep from its mouth. If it rose up against me, I would grab it by its jaw, strike it, and kill it.