19 Gideon replied, “Those were my brothers, the sons of my own mother. As surely as the LORD lives, if you had spared their lives, I would not kill you.”

Read Judges 8:19 Using Other Translations

And he said, They were my brethren, even the sons of my mother: as the LORD liveth, if ye had saved them alive, I would not slay you.
And he said, "They were my brothers, the sons of my mother. As the LORD lives, if you had saved them alive, I would not kill you."
“They were my brothers, the sons of my own mother!” Gideon exclaimed. “As surely as the LORD lives, I wouldn’t kill you if you hadn’t killed them.”