David took five stones with his sling – why ?? Some believe that Goliath had four relatives who were giants.
“These four were born to the giant in Gath, and fell by the hand of David, and by the hand of his servants.” (2nd Samuel 21:22)
If this is true, then what a faith David had ! He knew God could deliver him from 1 or 101 giants !
In sad contrast, the very same David, in 1st Samuel 27, feared that Saul would one day kill him, and he fled into the land of the Philistines, and consequently into a dark period of his life. This is what happens when we take our eyes off the Lord.“And David said in his heart, I shall now perish one day by the hand of Saul: there is nothing better for me than that I should speedily escape into the land of the Philistines; and Saul shall despair of me, to seek me any more in any coast of Israel: so shall I escape out of his hand. (1st Samuel 27:1)You can read the rest of chapter 27 to discover the trouble that David got himself into.