Judges 8:19 in the King James Version
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.
Context
18 Then he said to Zebah and Zalmunna, “What kind of men were they whom you killed at Tabor?” They answered, “They were like you. They all resembled the children of a king.”
19 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.”
20 He said to Jether his firstborn, “Get up and kill them!” But the youth didn’t draw his sword; for he was afraid, because he was yet a youth.