1 Samuel 17:33-37

Context
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. 17:36 Your servant has struck down both the lion and the bear. This uncircumcised Philistine will be just like one of them. ¹  For he has defied the armies of the living God!” 17:37 David went on to say, “The Lord who delivered me from the lion and the bear will also deliver me from the hand of this Philistine!” Then Saul said to David, “Go! The Lord will be with you.” ² 

1 Samuel 17:45-47

Context

17:45 But David replied to the Philistine, “You are coming against me with sword and spear and javelin. But I am coming against you in the name of the Lord of hosts, the God of Israel’s armies, whom you have defied! 17:46 This very day the Lord will deliver you into my hand! I will strike you down and cut off your head. This day I will give the corpses of the Philistine army to the birds of the sky and the wild animals of the land. Then all the land will realize that Israel has a God 17:47 and all this assembly will know that it is not by sword or spear that the Lord saves! For the battle is the Lord’s, and he will deliver you into our hand.”