The armies of Israel have drawn up against the armies of the Philistines, but not a single shot has been fired from any bow. The reason, of course, is Goliath, a mercenary of tremendous size and strength, renowned for his skill in combat. He's killed many men bare-handed, and no one wants to be next. David is barely a teen when he goes to the camp and sees what is going on. He offers to fight the giant, at which point he is brought before the king, who in turn attempts to dissuade the lad. Saul says, "You are not able to go out against this Philistine and fight him; you are only a boy, and he has been a fighting man from his youth" (1 Sam. 17:33 NIV). Sound advice, the likes of which I wager any of us would offer under the same circumstances. David replies:
Your servant has been keeping his father's sheep. When a lion or a bear came and carried off a sheep from the flock, I went after it, struck it, and rescued the sheep from its mouth. When it turned on me, I seized it by its hair, struck it and killed it. Your servant has killed both the lion and the bear; this uncircumcised Philistine will be like one of them, because he has defied the armies of the living God. The LORD who delivered me from the paw of the lion and the paw of the bear will deliver me from the hand of this Philistine. (verses 34-37 NIV)
Being a shepherd David learned lessons here that would carry him the rest of his life. The life of the shepherd was not a sweet little life with lambs around. It was a hard job, out in the field, months camping out in the wild on your own. And it had its effect. There is a settled confidence in the boy-he knows he has what it takes. But it is not an arrogance-he knows that God has been with him. He will charge Goliath, and take his best shot, trusting God will do the rest. That "knowing" is what we are after and it only comes through experience. And may I also point out that the experiences David speaks of here were physical in nature, they were dangerous, and they required courage.