Gath and Ashkelon were major Philistine cities. If people announced Saul’s death there, the Philistines would have the chance to celebrate. They could boast over Israel and praise their god Dagon, while mocking Israel’s God, Yahweh.
daughters of the Philistines: In ancient war culture, young women sometimes celebrated victories with songs (see Exodus 15:20–21; 1 Samuel 18:7).