20 And David rose early in the morning, and left the sheep with a keeper, and took the provisions, and went, as Jesse had commanded him; and he came to the encampment as the host was going forth to the battle line, shouting the war cry. 21 And Israel and the Philistines drew up for battle, army against army. 22 And David left the things in charge of the keeper of the baggage, and ran to the ranks, and went and greeted his brothers. 23 As he talked with them, behold, the champion, the Philistine of Gath, Goliath by name, came up out of the ranks of the Philistines, and spoke the same words as before. And David heard him. 24 All the men of Israel, when they saw the man, fled from him, and were much afraid. 25 And the men of Israel said, "Have you seen this man who has come up? Surely he has come up to defy Israel; and the man who kills him, the king will enrich with great riches, and will give him his daughter, and make his father's house free in Israel." 26 And David said to the men who stood by him, "What shall be done for the man who kills this Philistine, and takes away the reproach from Israel? For who is this uncircumcised Philistine, that he should defy the armies of the living God?"
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.