David has offered to go fight Goliath and is called before King Saul. 1 Sam.17:32 “Don’t worry about this Philistine,” David told Saul. “I’ll go fight him!”
33“Don’t be ridiculous!” Saul replied. “There’s no way you can fight this Philistine and possibly win! You’re only a boy, and he’s been a man of war since his youth.”
But David tells how God helped him kill a lion and a bear while he was watching his sheep. Saul has David put his armor on, but it doesn’t fit David. David simply chooses to go without the armor and just with his sling that he uses to defend the sheep. As David goes to meet Goliath, he picks up five smooth stones from the ground.
When Goliath sees David, just a boy, coming, he is disgusted and makes fun of him. David replies, 1 Sam.17:45“You come to me using sword, spear, and javelin. But I come to you in the name of the Lord All-Powerful, the God of the armies of Israel. You have said bad things about him. 46 Today the Lord will let me defeat you… Then all the world will know there is a God in Israel.” Then David loads the sling and slung the stone. It hit Goliath between the eyes, and he fell to the ground. David runs over, takes Goliath’s sword and decapitates the giant.
When the Philistine army saw what had happened, they ran. The Israelite army followed them and defeated them soundly.
Have you ever thought that you might be called to defend God to those who don’t believe? That is essentially what David is doing. The Philistines had their own gods and didn’t worship the one true God. David saw that his battle with Goliath was the Lord’s battle. God often works through humans and in this case, He was working through David. It was David’s actions that allowed the whole world to know that God rescues His people and they can be sure there really is a God.
I think this is still true today. God works through individuals to show who He is and to demonstrate His power. In life, I think we are to find our security in God, not in weapons, or money, or clever strategies. We can depend on our God who demonstrates His faithfulness to His people. To hear more about the story of David and Goliath, listen here: https://podpoint.com/light-of-christ-church-podcast/series/david-and-his-songs-the-early-years/the-lord-gives-me-the-victory
 Summarized from 1 Sam. 17:31-53