Judges 9:1
And Abimelech the son of Jerubbaal went to Shechem unto his mother’s brethren, and communed with them, and with all the family of the house of his mother’s father, saying, And Abimelech the son of Jerubbaal went to Shechem unto his mother’s brethren, and communed with them, and with all the family of the house of his mother’s father, saying,
After Gideon's death Israel forgot the Lord who had delivered them from all their enemies on every side. They showed no kindness to the house of Jerubbaal for all the goodness Gideon had shown to Israel. Instead they accepted his base-born son Abimelech as king, and this verse describes Abimelech's approach to his mother's brethren and to all the family of his mother's father's house at Shechem to secure that place. To sustain his power Abimelech then murdered all but one of Gideon's lawful children.
The verse shows that when people cast off the fear of God they soon depart from honor and integrity. Ingratitude toward God produces ingratitude and cruelty toward the human instruments God has used to bless His people. Appreciation of the Lord's mercy leads in turn to appreciation of those instruments.