So David prevailed over the Philistine with a sling and with a stone,.... And with them only, without any other warlike weapon:

and smote the Philistine, and slew him; smote him with the stone, which brought him to the ground, and then slew him with his own sword, as afterwards related:

but there was no sword in the hand of David; when he engaged with the Philistine, and smote him, for he had put off all his armour, 1 Samuel 17:39.

1 Samuel 17:50 contains a remark by the historian with reference to the result of the conflict: "Thus was David stronger than the Philistine, with a sling and stone, and smote the Philistine, and slew him without a sword in his hand." And then in 1 Samuel 17:51 the details are given, namely, that David cut off the head of the fallen giant with his own sword. Upon the downfall of their hero the Philistines were terrified and fled; whereupon the Israelites rose up with a cry to pursue the flying foe, and pursued them "to a valley, and to the gates of Ekron." The first place mentioned is a very striking one. The "valley" cannot mean the one which divided the two armies, according to 1 Samuel 17:3, not only because the article is wanting, but still more from the facts themselves. For it is neither stated, nor really probable, that the Philistines had crossed that valley, so as to make it possible to pursue them into it again. But if the word refers to some other valley, it seems very strange that nothing further should be said about it. Both these circumstances render the reading itself, ניא, suspicious, and give great probability to the conjecture that ניא is only a copyist's error for Gath, which is the rendering given by the lxx, especially when taken in connection with the following clause, "to Gath and to Ekron" (1 Samuel 17:52).

So David prevailed over the Philistine with a sling and with a stone, and smote the Philistine, and slew him; but there was no sword in the hand of David.

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!