(51) And when the Philistines saw their champion was dead, they fled.--The Philistines had agreed to consider this single combat as decisive. They had no fears as to its result, and when they saw their boasted champion fall they were seized with a sudden panic. Their adversaries, the children of Israel, on the other hand, seeing the unarmed shepherd boy with the head of the great warrior who had so long defied them in his hand, felt that the old power had come back to them, and that once more their Invisible King was with them, so they at once, with an irresistible shout, charged their dismayed foes, and the battle, as far as the Philistines were concerned, became a total rout.

17:48-58 See how frail and uncertain life is, even when a man thinks himself best fortified; how quickly, how easily, and by how small a matter, the passage may be opened for life to go out, and death to enter! Let not the strong man glory in his strength, nor the armed man in his armour. God resists the proud, and pours contempt on those who defy him and his people. No one ever hardened his heart against God and prospered. The history is recorded, that all may exert themselves for the honour of God, and the support of his cause, with bold and unshaken reliance on him. There is one conflict in which all the followers of the Lamb are, and must be engaged; one enemy, more formidable than Goliath, still challenges the armies of Israel. But resist the devil, and he will flee from you. Go forth to battle with the faith of David, and the powers of darkness shall not stand against you. But how often is the Christian foiled through an evil heart of unbelief!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 Psalm 9:1.