The Philistines stood on one hill and the Israelites stood on another, with the valley between them.
It was not long ago that the Philistines were soundly beaten, and put to the worse, before Israel, and they would have been totally routed if Saul's rashness had not prevented; but here we have them making head again. Observe, I. How they defied Israel with their armies, Sa1 17:1.
Commenting on 1 Samuel 17:1-11
And the Philistines stood on a mountain on the one side, and Israel stood on a mountain on the other side, Before the Israelites are said to encamp in or by the valley; but here they are said to take the higher ground, and face the Philistines, who were on a mountain or hill on the other side over against them, which Kimchi reconciles thus...
And it came to pass, when the [evil] spirit from God was upon Saul, that David took an harp, and played with his hand: so Saul was refreshed, and was well, and the evil spirit departed from him. (g) God would have Saul receive this benefit from David's hand, that his condemnation might be even more evident, for his cruel hate toward him.
Commenting on 1 Samuel 17:1-3