Judges 9:5
And he went unto his father’s house at Ophrah, and slew his brethren the sons of Jerubbaal, being threescore and ten persons, upon one stone: notwithstanding yet Jotham the youngest son of Jerubbaal was left; for he hid himself. And he went unto his father’s house at Ophrah, and slew his brethren the sons of Jerubbaal, being threescore and ten persons, upon one stone: notwithstanding yet Jotham the youngest son of Jerubbaal was left; for he hid himself.
After Gideon's death his base-born son Abimelech was accepted by Israel as king and murdered all but one of Gideon's lawful children upon one stone at his father's house at Ophrah to sustain his power. The one left was Jotham the youngest son of Jerubbaal, who escaped because he hid himself. The killing took place when Israel had forgotten what they owed to God for delivering them from their enemies on every side.
They showed no kindness to the house of Jerubbaal in return for all the goodness Gideon had shown to Israel as judge and deliverer. Casting off the fear of God leads to departing from honor and integrity. Ingratitude toward God produces ingratitude and cruelty toward those whom God employed as instruments to bless His people, while appreciation of the Lord's mercy leads to appreciation of servants such as Gideon.