Exodus 32:27-29

Living Bible

²⁷ He told them, “Jehovah the God of Israel says, ‘Get your swords and go back and forth from one end of the camp to the other and kill even your brothers, friends, and neighbors.’” ²⁸ So they did, and about three thousand men died that day.

²⁹ Then Moses told the Levites, “Today you have ordained yourselves for the service of the Lord, for you obeyed him even though it meant killing your own sons and brothers; now he will give you a great blessing.”