Exodus 32:28

28 The sons of Levi did as Moses commanded, and about three thousand of the people fell on that day.

Exodus 32:28 In-Context

26 then Moses stood in the gate of the camp, and said, "Who is on the Lord's side? Come to me!" And all the sons of Levi gathered around him.
27 He said to them, "Thus says the Lord, the God of Israel, "Put your sword on your side, each of you! Go back and forth from gate to gate throughout the camp, and each of you kill your brother, your friend, and your neighbor.' "
28 The sons of Levi did as Moses commanded, and about three thousand of the people fell on that day.
29 Moses said, "Today you have ordained yourselves for the service of the Lord, each one at the cost of a son or a brother, and so have brought a blessing on yourselves this day."
30 On the next day Moses said to the people, "You have sinned a great sin. But now I will go up to the Lord; perhaps I can make atonement for your sin."
New Revised Standard Version Bible, copyright 1989, Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.