20 David was up at the crack of dawn and, having arranged for someone to tend his flock, took the food and was on his way just as Jesse had directed him. He arrived at the camp just as the army was moving into battle formation, shouting the war cry. 21 Israel and the Philistines moved into position, facing each other, battle-ready. 22 David left his bundles of food in the care of a sentry, ran to the troops who were deployed, and greeted his brothers. 23 While they were talking together, the Philistine champion, Goliath of Gath, stepped out from the front lines of the Philistines, and gave his usual challenge. David heard him. 24 The Israelites, to a man, fell back the moment they saw the giant - totally frightened. 25 The talk among the troops was, "Have you ever seen anything like this, this man openly and defiantly challenging Israel? The man who kills the giant will have it made. The king will give him a huge reward, offer his daughter as a bride, and give his entire family a free ride." 26 David, who was talking to the men standing around him, asked, "What's in it for the man who kills that Philistine and gets rid of this ugly blot on Israel's honor? Who does he think he is, anyway, this uncircumcised Philistine, taunting the armies of God-Alive?"
Matthew Henry's Commentary on 1 Samuel 17:20-26
Commentary on 1 Samuel 17:12-30
(Read 1 Samuel 17:12-30)
Jesse little thought of sending his son to the army at that critical juncture; but the wise God orders actions and affairs, so as to serve his designs. In times of general formality and lukewarmness, every degree of zeal which implies readiness to go further, or to venture more in the cause of God than others, will be blamed as pride and ambition, and by none more than by near relations, like Eliab, or negligent superiors. It was a trial of David's meekness, patience, and constancy. He had right and reason on his side, and did not render railing for railing; with a soft answer he turned away his brother's wrath. This conquest of his own passion was more honourable than that of Goliath. Those who undertake great and public services, must not think it strange if they are spoken ill of, and opposed by those from whom they expect support and assistance. They must humbly go on with their work, in the face not only of enemies' threats, but of friends' slights and suspicions.