Exodus 32:27-29

Young's Literal Translation

²⁷ and he saith to them, `Thus said Jehovah, God of Israel, Put each his sword by his thigh, pass over and turn back from gate to gate through the camp, and slay each his brother, and each his friend, and each his relation.'

²⁸ And the sons of Levi do according to the word of Moses, and there fall of the people on that day about three thousand men,

²⁹ and Moses saith, `Consecrate your hand to-day to Jehovah, for a man [is] against his son, and against his brother, so as to bring on you to-day a blessing.'