Adam Clarke on 1 Samuel 17:1

Now the Philistines gathered together - Calmet thinks that this war happened eight years after the anointing of David, and ten or twelve years after the war with the Amalekites. We have already seen that there was war between Saul and the Philistines all his days. See 1Sam 14:52.

Shochoh and Azekah - Places which lay to the south of Jerusalem and to the west of Bethlehem; about five leagues from the former. Ephes-dammim was somewhere in the vicinity, but it is not known where. See Calmet.