Zebul his officer - פקידו pekido, his overseer; probably governor of Shechem in his absence.
Seditious and lawless acts Judges 9:25-26 now broke out into open rebellion. It was at an idolatrous feast in the house of Baal-berith, on occasion of the vintage, and when they were excited with wine, that the rebellion was matured. Those present began to “curse Abimelech,” to speak insultingly of him, and to revile him (compare Leviticus 20:9; 2 Samuel 19:21; Isaiah 8:21). Gaal, the son of Ebed, who was watching the opportunity, immediately incited them to revolt from the dominion of Abimelech, offering himself to be their captain; adding a message of defiance to Abimelech, addressed, probably, to Zebul, who was present but too weak to resent it on the spot.
Judges 9:27
Made merry - The word translated “merry” occurs only here and in Leviticus 19:24. Its etymology gives the sense of “praises”, “thanksgivings”; and its use in these two passages rather indicates that the fruits themselves which were brought to the House of God with songs of praise, and eaten or drunken with religious service, were so called. The thank-offerings would be a portion of the new wine of the vintage which they had just gathered in.
Judges 9:28
Shechem is another designation of Abimelech. Sheehem means the son and heir of Sheehem, Abimelech‘s mother being a Canaanite Judges 9:18.