A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
1 Kings (1 Samuel) 17:1
sa1 17:1THE ISRAELITES AND PHILISTINES BEING READY TO BATTLE. (Sa1 17:1-3)
the Philistines gathered together their armies--twenty-seven years after their overthrow at Michmash. Having now recovered their spirits and strength, they sought an opportunity of wiping out the infamy of that national disaster, as well as to regain their lost ascendency over Israel.
Shocoh--now Shuweikeh, a town in the western plains of Judah (Jos 15:35), nine Roman miles from Eleutheropolis, toward Jerusalem [ROBINSON].
Azekah--a small place in the neighborhood.
Ephes-dammim--or, "Pas-dammim" (Ch1 11:13), "the portion" or "effusion of blood," situated between the other two.
1 Kings (1 Samuel) 17:2
sa1 17:2valley of Elah--that is, "the Terebinth," now Wady Er-Sumt [ROBINSON]. Another valley somewhat to the north, now called Wady Beit Hanina, has been fixed on by the tradition of ages.
1 Kings (1 Samuel) 17:4
sa1 17:4GOLIATH CHALLENGES A COMBAT. (Sa1 17:4-11)
a champion--Hebrew, a "man between two"; that is, a person who, on the part of his own people, undertook to determine the national quarrel by engaging in single combat with a chosen warrior in the hostile army.
1 Kings (1 Samuel) 17:5
sa1 17:5helmet of brass--The Philistine helmet had the appearance of a row of feathers set in a tiara, or metal band, to which were attached scales of the same material, for the defense of the neck and the sides of the face [OSBORN].
a coat of mail--a kind of corslet, quilted with leather or plates of metal, reaching only to the chest, and supported by shoulder straps, leaving the shoulders and arms at full liberty.
1 Kings (1 Samuel) 17:6
sa1 17:6greaves of brass--boots, terminating at the ankle, made in one plate of metal, but round to the shape of the leg, and often lined with felt or sponge. They were useful in guarding the legs, not only against the spikes of the enemy, but in making way among thorns and briers.
a target of brass--a circular frame, carried at the back, suspended by a long belt which crossed the breast from the shoulders to the loins.
1 Kings (1 Samuel) 17:7
sa1 17:7staff of his spear--rather under five feet long, and capable of being used as a javelin (Sa1 19:10). It had an iron head.
one bearing a shield--In consequence of their great size and weight, the Oriental warrior had a trusty and skilful friend, whose office it was to bear the large shield behind which he avoided the missile weapons of the enemy. He was covered, cap-a-pie, with defensive armor, while he had only two offensive weapons--a sword by his side and a spear in his hand.
1 Kings (1 Samuel) 17:8
sa1 17:8I defy the armies of Israel . . .; give me a man, that we may fight together--In cases of single combat, a warrior used to go out in front of his party, and advancing towards the opposite ranks, challenge someone to fight with him. If his formidable appearance, or great reputation for physical strength and heroism, deterred any from accepting the challenge, he used to parade himself within hearing of the enemy's lines, specify in a loud, boastful, bravado style, defying them, and pouring out torrents of abuse and insolence to provoke their resentment.
1 Kings (1 Samuel) 17:17
sa1 17:17DAVID ACCEPTS THE CHALLENGE, AND SLAYS HIM. (1Sa. 17:12-58)
Take now for thy brethren an ephah of this parched corn, and these ten loaves--In those times campaigns seldom lasted above a few days at a time. The soldiers were volunteers or militia, who were supplied with provisions from time to time by their friends at home.
1 Kings (1 Samuel) 17:18
sa1 17:18carry these ten cheeses to the captain--to enlist his kind attention. Oriental cheeses are very small; and although they are frequently made of so soft a consistence as to resemble curds, those which David carried seem to have been fully formed, pressed, and sufficiently dried to admit of their being carried.
take their pledge--Tokens of the soldiers' health and safety were sent home in the convenient form of a lock of their hair, or piece of their nail, or such like.
1 Kings (1 Samuel) 17:20
sa1 17:20David left the sheep with a keeper--This is the only instance in which the hired shepherd is distinguished from the master or one of his family.
trench--some feeble attempt at a rampart. It appears (see Margin) to have been formed by a line of carts or chariots, which, from the earliest times, was the practice of nomad people.
1 Kings (1 Samuel) 17:22
sa1 17:22left his carriage in the hand of the keeper of the carriage--to make his way to the standard of Judah.
1 Kings (1 Samuel) 17:25
sa1 17:25make his father's house free in Israel--His family should be exempted from the impositions and services to which the general body of the Israelites were subjected.
1 Kings (1 Samuel) 17:34
sa1 17:34a lion, and a bear--There were two different rencontres, for those animals prowl alone. The bear must have been a Syrian bear, which is believed to be a distinct species, or perhaps a variety, of the brown bear. The beard applies to the lion alone. Those feats seem to have been performed with no weapons more effective than the rude staves and stones of the field, or his shepherd's crook.
1 Kings (1 Samuel) 17:37
sa1 17:37The Lord that delivered me--It would have been natural for a youth, and especially an Oriental youth, to make a parade of his gallantry. But David's piety sank all consideration of his own prowess and ascribed the success of those achievements to the divine aid, which he felt assured would not be withheld from him in a cause which so intimately concerned the safety and honor of His people.
Saul said unto David, Go, and the Lord be with thee--The pious language of the modest but valiant youth impressed the monarch's heart. He felt that it indicated the true military confidence for Israel, and, therefore, made up his mind, without any demur, to sanction a combat on which the fate of his kingdom depended, and with a champion supporting his interests apparently so unequal to the task.
1 Kings (1 Samuel) 17:38
sa1 17:38Saul armed David with his armour--The ancient Hebrews were particularly attentive to the personal safety of their warriors, and hence Saul equipped the youthful champion with his own defensive accoutrements, which would be of the best style. It is probable that Saul's coat of mail, or corslet, was a loose shirt, otherwise it could not have fitted both a stripling and a man of the colossal stature of the king.
1 Kings (1 Samuel) 17:40
bag--or scrip for containing his daily food.
sling--The sling consisted of a double rope with a thong, probably of leather, to receive the stone. The slinger held a second stone in his left hand. David chose five stones, as a reserve, in case the first should fail. Shepherds in the East carry a sling and stones still, for the purpose of driving away, or killing, the enemies that prowl about the flock.
1 Kings (1 Samuel) 17:42
sa1 17:42the Philistine said . . . said David to the Philistine--When the two champions met, they generally made each of them a speech, and sometimes recited some verses, filled with allusions and epithets of the most opprobrious kind, hurling contempt and defiance at one another. This kind of abusive dialogue is common among the Arab combatants still. David's speech, however, presents a striking contrast to the usual strain of these invectives. It was full of pious trust, and to God he ascribed all the glory of the triumph he anticipated.
1 Kings (1 Samuel) 17:49
sa1 17:49smote the Philistine in his forehead--At the opening for the eyes--that was the only exposed part of his body.
1 Kings (1 Samuel) 17:51
sa1 17:51cut 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.
1 Kings (1 Samuel) 17:52
sa1 17:52Shaaraim--(See Jos 15:36).
1 Kings (1 Samuel) 17:54
sa1 17:54tent--the sacred tabernacle. David dedicated the sword of Goliath as a votive offering to the Lord.
1 Kings (1 Samuel) 17:55
sa1 17:55Saul . . . said unto Abner . . . whose son is this youth?--A young man is more spoken of in many Eastern countries by his father's name than his own. The growth of the beard, and other changes on a now full-grown youth, prevented the king from recognizing his former favorite minstrel [Sa1 16:23].