Judges 9:50

‘ Then Abimelech went to Thebez, and encamped against Thebez, and took it.'

The insurrection in Shechem had spread. Abimelech had not been reigning as a prince of Israel long and already there was general dissatisfaction. It was not only his kingship at Shechem, with their syncretistic beliefs, that was in question, but his princeship over his part of Israel. Thebez was a fortified city in the hill country of Ephraim. It is modern Tubas about ten miles (sixteen kilometres) north of Nablus and twelve miles (nineteen kilometres) north east of Shechem on the road to Beth-shan. But Abimelech was an able general, and besieged it and took it.

It is possible that the city had sheltered refugees from Shechem and had refused to give them up. Or that they had refused Abimelech entrance when he had demanded it in order to search for refugees. Or even that they had withheld taxes levied by him. This was the problem with having a prince. He expected some financial gain from it. But in some way they had indicated their unwillingness now to accept him as prince.