'Kings' in the Bible

Now when Saul had taken the kingdom over Israel, he fought against all his enemies on every side, against Moab, and against the children of Ammon, and against Edom, and against the kings of Zobah, and against the Philistines: and wherever he turned himself, he put [them] to the worse.

Then Achish gave him Ziklag that day: why Ziklag pertains to the kings of Judah to this day.