See opening of the letters of Abimelech of Tyre, Bezold's Oriental Diplomacy, Nos.
David's friendly relations with the Philistines find a parallel in Isaac's covenant with Abimelech.
Abimelech, warned by his deputy Zebul, left his residence at Arumah and approached the city.
Abimelech is called "king of the Philistines," but the title is clearly an anachronism.
On the death of Gideon, Abimelech set himself to assert the authority which his father had earned, and through the influence of his mother's clan won over the citizens of Shechem.