Judges 1:18

Judah took Gaza. It seems that the tribe of Judah now carried on the campaign alone. They swung from the Negeb over to the maritime plain and headed north, attacking the coastal cities. The southernmost of these was Gaza, which they captured by storm, along with Askelon and Ekron. Thus three centers of the Philistine confederacy fell before the Israelites. However, it seems that the Hebrews overthrew these strongholds by swift, surprise attacks, but were not able to hold them after the Philistines regrouped and counter-attacked, for the next verse states that Judah could not drive out the inhabitants of the valley (see also ch. 3:3).