Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[240] A little while after this festival, the Shechemites, who had now repented themselves of having slain the sons of Gideon, drove Abimelech away, both from their city and their tribe; whereupon he contrived how he might distress their city. Now at the season of vintage, the people were afraid to go out and gather their fruits, for fear Abimelech should do them some mischief. Now it happened that there had come to them a man of authority, one Gaal, that sojourned with them, having his armed men and his kinsmen with him; so the Shechemites desired that he would allow them a guard during their vintage; whereupon he accepted of their desires, and so the people went out, and Gaal with them at the head of his soldiery. So they gathered their fruit with safety; and when they were at supper in several companies, they then ventured to curse Abimelech openly; and the magistrates laid ambushes in places about the city, and caught many of Abimelech's followers, and destroyed them.