Charles Ellicott Commentary Judges 9:25

"And the men of Shechem set liers-in-wait for him on the tops of the mountains, and they robbed all that came along that way by them: and it was told Abimelech." — Judges 9:25 (ASV)

Set liers in wait for him. —The “for him” does not necessarily mean “to seize him,” but to his disadvantage. The disaffection began to show itself, as has so often been the case in Palestine from the days of Saul to those of Herod, by the rise of brigandage, rendering all government precarious, and providing a refuge for all dangerous and discontented spirits. Josephus says that Abimelech was expelled from Shechem, and even from the tribe of Ephraim (Antt. v. 1, § 3).

In the top of the mountains. —Especially Ebal and Gerizim.