NOTES for Sa1 17:1-58
The story of David's combat with Goliath is perhaps the most popular episode in the entire account of David's life. This is quite understandable, for here we see David's first great deed, which casts a bright light on all his later exploits.
David, who has neither an imposing appearance nor weapons comparable to those of his enemy, defeats Goliath, the mightiest of the Philistine warriors. Of course, David won while fighting for a righteous cause, with the Lord on his side. But receiving His power requires turning toward Him. David possesses precisely this orientation toward God and faithfulness to Him.
A small stone from a sling brought down the enormous champion. What people regard as strong and invincible has no significance in the Lord's eyes, just as many things routinely valued by people have no value to Him. Time and again, what was weak, rejected, and despised proved to be precisely what the Lord chose and used to accomplish His will.