Hawker's Poor man's commentary
1 Samuel 17:48-51
(48) В¶ And it came to pass, when the Philistine arose, and came and drew nigh to meet David, that David hasted, and ran toward the army to meet the Philistine. (49) And David put his hand in his bag, and took thence a stone, and slang it, and smote the Philistine in his forehead, that the stone sunk into his forehead; and he fell upon his face to the earth. (50) 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. (51) Therefore David ran, and stood upon the Philistine, and took his sword, and drew it out of the sheath thereof, and slew him, and cut off his head therewith. And when the Philistines saw their champion was dead, they fled.
Here we have the termination of the battle, in the fall of Goliath, and a tremendous one it was. So simple means as a stone, for the weapon of destruction, and slung by so youthful an hand, serve at once to show the arm of the God of Israel engaged in it. Blind indeed, must be that eye that doth not recognize such a visible display. One of the Jewish Rabbins hath observed upon it, but by what authority I know not, that Goliath in his rage and contempt of David, when he said Come, and I will give thy flesh to the fowls of the air, threw up the upper part of his helmet, and thereby left his forehead bare for the stone of David to have the easier entrance. Whether this were so or not, no doubt the Lord who presided over the battle and ordered all, so disposed of, everything in it, as to facilitate the event he had ordained. But is it not delightful to see, that the very weapons of the Philistine's own pride and ostentation, are made subservient to his own destruction. Reader! do not fail to connect with this view of Goliath, his total destruction whom Goliath represented, and by the conversion of his own weapons to his own overthrow. When the devil tempted Adam to transgress, little did he think, that this very transgression should lay the foundation for all the blessed things contained in our redemption by Jesus. And when in after ages, the Jews led on by his temptations, nailed Jesus to the cross, little did he then consider, that that very cross would become the glorious cause of his people's salvation, and their everlasting joy through all eternity. I would desire grace from the Holy Ghost, ever to keep such evidences of the Lord's overruling all the church's enemies, to his own glory and his people's good, in view. It would serve to prove in many lesser instances, where perhaps things are not so plainly manifested, the truth of that precious scripture, that the very wrath of man (and may we not add devils) shall praise him, and the remainder of wrath the Lord will restrain. Psalms 76:10.