That the author uses “spoil” to refer to the clothing hints that this is war. For the term is a military term, used only one other time in the Old Testament, in 2 Samuel 2:21 for armaments taken off a slain soldier. Its use here suggests that Samson’s personal vendetta has been escalated to a war.
19 And the Spirit of the LORD rushed upon him, and he went down to Ashkelon and struck down thirty men of the town and took their spoil and gave the garments to those who had told the riddle. In hot anger he went back to his father’s house.