New Defender's Study Bible Notes
9:1 went to Shechem. The rebellious and ambitious Abimelech had apparently been brought up in Shechem by Gideon’s concubine and had acquired enough influence over the Shechemites to persuade them to follow him in setting himself up as king of Israel. This involved murdering all his brothers (except Jotham, who escaped), and then establishing his supposed capital in Shechem (Judges 9:3-6). Abimelech thus presumptuously assumed by force a position which had been declined by his father.