What does Judges 9:24 mean?
This verse shows God's motive in clear terms: He is repaying both Abimelech and the leaders of Shechem for the slaughter of Gideon's sons (Judges 9:1–6). Abimelech and his hired goons were the ones to kill the sons of Jerubbaal (Judges 6:32), but the leaders of Shechem arranged for that to happen. They paid for the hoodlums who helped Abimelech, and accepted his demand to become their ruler.The blood of the sons of God's deliverer (Judges 6:11–12; 8:33–34) was on the hands of Abimelech and his subjects. Both would be made to pay by the Lord Himself.
The prior verse indicated God sent "an evil spirit" between Abimelech and the leaders of Shechem. This is not the only time Scripture mentions the Lord using this technique (1 Samuel 16:14). The terminology here might refer to a literal demon, or more likely, an attitude of hatred and anger. Either way, God drives these evildoers to destroy each other, in judgment against their sin.