Here is 1. The engagement between the two champions, Sa1 17:48. To this engagement the Philistine advanced with a great deal of state and gravity; if he must encounter a pigmy, yet it shall be with the magnificence of a giant and a grandee. This is intimated in the manner of expression: He arose, and came, and drew nigh, like a stalking mountain, overlaid with brass and iron, to meet David. David advanced with no less activity and cheerfulness, as one that aimed more to do execution than to make a figure: He hasted, and ran, being lightly clad, to meet the Philistine. We may imagine with what tenderness and compassion the Israelites saw such a pleasing youth as this throwing himself into the mouth of destruction, but he knew whom he had believed and for whom he acted. 2. The fall of Goliath in this engagement. He was in no haste, because in no fear, but confident that he should soon at one stroke cleave his adversary's head; but, while he was preparing to do it solemnly, David did his business effectually, without any parade: he slang a stone which hit him in the forehead, and, in the twinkling of an eye, fetched him to the ground, Sa1 17:49. Goliath knew there were famous slingers in Israel (Jdg 20:16), yet was either so forgetful or presumptuous as to go with the beaver of his helmet open, and thither, to the only part left exposed, not so much David's art as God's providence directed the stone, and brought it with such force that it sunk into his head, notwithstanding the impudence with which his forehead was brazened. See how frail and uncertain life is, even when it thinks itself best fortified, and how quickly, how easily, and with how small a matter, the passage may be opened for life to go out and death to enter. Goliath himself has not power over the spirit to retain the spirit, Ecc 8:8. Let not the strong man glory in his strength, nor the armed man in his armour. See how God resists the proud and pours contempt upon those that bid defiance to him and his people. None ever hardened his heart against God and prospered. One of the Rabbin thinks that when Goliath said to David, Come, and I will give thy flesh to the fowls of the air, he threw up his head so hastily that his helmet fell off, and so left his broad forehead a fair mark for David. To complete the execution, David drew Goliath's own sword, a two-handed weapon for David, and with it cut off his head, Sa1 17:51. What need had David to take a sword of his own? his enemy's sword shall serve his purpose, when he has occasion for one. God is greatly glorified when his proud enemies are cut off with their own sword and he makes their own tongues to fall upon them, Psa 64:8. David's victory over Goliath was typical of the triumphs of the son of David over Satan and all the powers of darkness, whom he spoiled, and made a show of them openly (Col 2:15), and we through him are more than conquerors. 3. The defeat of the Philistines' army hereupon. They relied wholly upon the strength of their champion, and therefore, when they saw him slain, they did not, as Goliath had offered, throw down their arms and surrender themselves servants to Israel (Sa1 17:9), but took to their heels, being wholly dispirited, and thinking it to no purpose to oppose one before whom such a mighty man had fallen: They fled (Sa1 17:51), and this put life into the Israelites, who shouted and pursued them (David, it is probable, leading them on in the pursuit) even to the gates of their own cities, Sa1 17:52. In their return from the chase they seized all the baggage, plundered the tents (Sa1 17:53), and enriched themselves with the spoil. 4. David's disposal of his trophies, Sa1 17:54. He brought the head of the Philistine to Jerusalem, to be a terror to the Jebusites, who held the strong-hold of Sion: it is probable that he carried it in triumph to other cities. His armour he laid up in his tent; only the sword was preserved behind the ephod in the tabernacle, as consecrated to God, and a memorial of the victory to his honour, Sa1 21:9. 5. The notice that was taken of David. Though he had been at court formerly, yet, having been for some time absent (Sa1 17:15), Saul had forgotten him, being melancholy and mindless, and little thinking that his musician would have spirit enough to be his champion; and therefore, as if he had never seen him before, he asked whose son he was. Abner was a stranger to him, but brought him to Saul (Sa1 17:57), and he gave a modest account of himself, Sa1 17:58. And now he was introduced to the court with much greater advantages than before, in which he owned God's hand performing all things for him.

When the Philistines saw their champion was dead, they fled - They were panic-struck; and not being willing to fulfill the condition which was stipulated by Goliath, they precipitately left the field. The Israelites took a proper advantage of these circumstances, and totally routed their enemies.

Therefore David ran and stood upon the Philistine,.... Upon his carcass, as it lay prostrate on the ground, and trampled on him, in just contempt of him who had defied, reproached, and despised the armies of Israel:

and took his sword, and drew it out of the sheath thereof; which no doubt was a very large one, and required a good deal of strength to unsheathe it, and use it; and therefore either David, though so very young, was naturally very strong, or he had at this time a more than ordinary measure of strength given him:

and slew him; for it seems that by the blow of the stone he was only stunned, and fell to the ground, but still had life in him, which David soon put an end to by his own sword:

and cut off his head therewith; by which it would appear to both armies looking on that his business was done, and he was thoroughly dispatched:

and when the Philistines saw their champion was dead; of which the cutting off his head was a demonstrative proof, and which they could discern at a distance:

they fled; being struck with a panic at this unexpected event, and no doubt by the Lord; for otherwise, had they given themselves the least time to reflect on their own numbers and strength, they had no just occasion to flee; their safety not depending on a single man, though ever so strong: upon this occasion David penned the ninth psalm; see Psa 9:1.

cut off his head--not as an evidence of the giant's death, for his slaughter had been effected in presence of the whole army, but as a trophy to be borne to Saul. The heads of slain enemies are always regarded in the East as the most welcome tokens of victory.