1 Samuel 17:19

“Now Saul, and they, etc.] That is, the sons of Jesse, and brethren of David: and all the men of Israel; the soldiers in the army: were in the valley Elah; or “by” it, near unto it; for they were set in array on the mountain on the side of it: fighting with the Philistines; not actually engaged in battle, but drawn up for it; prepared and in readiness to engage whenever it was necessary, or they were obliged to it; and perhaps there might be now and then some skirmishes in the outer parts of the camp.”

“Fighting - That is, in a posture and readiness to fight with them; as it is explained, Sa1 17:20-21. 1 Kings (1 Samuel) 17:20”

“the valley: Dr. Richardson says, that in about twenty minutes, in an easterly direction, form the cave of St. John (which is about two hours or six miles, in a westerly direction, from Jerusalem), they came to the valley of Elah; which position seems to agree with that of Shochoh and Azekah. He describes it as "a small valley, and the place of the encampment is pointed out where it narrows into a broad, deep ravine; part of it was in crop, and part of it was under the plough, which was drawn by a couple of oxen. A small stream, which had shrunk almost under its stony bed, passes through it from east to west, from which we are informed that David chose out five smooth stones, and hasted and…”