Exodus 32:27 in the King James Version
And he said unto them, Thus saith the LORD God of Israel, Put every man his sword by his side, and go in and out from gate to gate throughout the camp, and slay every man his brother, and every man his companion, and every man his neighbour.
Context
26 then Moses stood in the gate of the camp, and said, “Whoever is on the LORD’s side, come to me!” All the sons of Levi gathered themselves together to him.
27 He said to them, “The LORD, the God of Israel, says, ‘Every man put his sword on his thigh, and go back and forth from gate to gate throughout the camp, and every man kill his brother, and every man his companion, and every man his neighbor.’”
28 The sons of Levi did according to the word of Moses. About three thousand men fell of the people that day.