Self-preservation is a powerful instinct
1 Sam 17:8-11
8 He stood and shouted to the ranks of Israel, “Why have you come out to draw up for battle? Am I not a Philistine, and are you
not servants of Saul? Choose a man for yourselves, and let him come down to me. 9 If he is able to fight with me and kill me, then we will be your
servants. But if I prevail against him and kill him, then you shall be our servants and serve us.” 10 And the Philistine said, “I defy the ranks of Israel
this day. Give me a man, that we may fight together.” 11 When Saul and all Israel heard these words of the Philistine, they were dismayed and greatly
afraid.
Conviction is also quite powerful
1 Sam 17:26
26 And David said to the men who stood by him, “What shall be done for the man who kills this Philistine and takes away the
reproach from Israel? For who is this uncircumcised Philistine, that he should defy the armies of the living God?”
1 Sam 17:32-37
32 And David said to Saul, “Let no man's heart fail because of him. Your servant will go and fight with this Philistine.” 33 And Saul
said to David, “You are not able to go against this Philistine to fight with him, for you are but a youth, and he has been a man of war from his
youth.” 34 But David said to Saul, “Your servant used to keep sheep for his father. And when there came a lion, or a bear, and took a lamb from the
flock, 35 I went after him and struck him and delivered it out of his mouth. And if he arose against me, I caught him by his beard and struck him and
killed him. 36 Your servant has struck down both lions and bears, and this uncircumcised Philistine shall be like one of them, for he has defied the
armies of the living God.” 37 And David said, “The LORD who delivered me from the paw of the lion and from the paw of the bear will deliver me from
the hand of this Philistine.” And Saul said to David, “Go, and the LORD be with you!”
Victory belongs to the powerful
1 Sam 17: 45-50
45 Then David said to the Philistine, “You come to me with a sword and with a spear and with a javelin, but I come to you in the
name of the LORD of hosts, the God of the armies of Israel, whom you have defied. 46 This day the LORD will deliver you into my hand, and I will strike
you down and cut off your head. And I will give the dead bodies of the host of the Philistines this day to the birds of the air and to the wild beasts of
the earth, that all the earth may know that there is a God in Israel, 47 and that all this assembly may know that the LORD saves not with sword and
spear. For the battle is the LORD's, and he will give you into our hand.”
48 When the Philistine arose and came and drew near to meet David, David ran quickly toward the battle line to meet the Philistine. 49 And David put
his hand in his bag and took out a stone and slung it and struck the Philistine on his forehead. The stone sank into his forehead, and he fell on his
face to the ground.
50 So David prevailed over the Philistine with a sling and with a stone, and struck the Philistine and killed him. There was no sword in the hand of
David.