Exodus 32:21-28

21And Moses said to Aaron, “What did this people do to you that you have brought so great a sin upon them?”

22So Aaron said, “Do not let the anger of my lord become hot. You know the people, that they are set on evil.

23For they said to me, ‘Make us gods that shall go before us; as for this Moses, the man who brought us out of the land of Egypt, we do not know what has become of him.’

24And I said to them, ‘Whoever has any gold, let them break it off.’ So they gave it to me, and I cast it into the fire, and this calf came out.”

25Now when Moses saw that the people were unrestrained (for Aaron had not restrained them, to their shame among their enemies),

26then Moses stood in the entrance of the camp, and said, “Whoever is on the Lord’s side—come to me!” And all the sons of Levi gathered themselves together to him.

27And he said to them, “Thus says the Lord God of Israel: ‘Let every man put his sword on his side, and go in and out from entrance to entrance throughout the camp, and let every man kill his brother, every man his companion, and every man his neighbor.’ ”

28So the sons of Levi did according to the word of Moses. And about three thousand men of the people fell that day.