Then Moses said to Aaron, "What did this people do to you, that you have brought such great sin upon them?" Aaron said, "Do not let the anger of my lord burn; you know the people yourself, that they are prone to evil. For they said to me, 'Make a god for us who will go before us; for this Moses, the man who brought us up from the land of Egypt, we do not know what has become of him.' I said to them, 'Whoever has any gold, let them tear it off.' So they gave it to me, and I threw it into the fire, and out came this calf."
Now when Moses saw that the people were out of control--for Aaron had let them get out of control to be a derision among their enemies--then Moses stood in the gate of the camp, and said, "Whoever is for the LORD, come to me!" And all the sons of Levi gathered together to him. He said to them, "Thus says the LORD, the God of Israel, 'Every man of you put his sword upon his thigh, and go back and forth from gate to gate in the camp, and kill every man his brother, and every man his friend, and every man his neighbor.' " So the sons of Levi did as Moses instructed, and about three thousand men of the people fell that day.
Then Moses said, "Dedicate yourselves today to the LORD --for every man has been against his son and against his brother--in order that He may bestow a blessing upon you today." On the next day Moses said to the people, "You yourselves have committed a great sin; and now I am going up to the LORD, perhaps I can make atonement for your sin."
Then Moses returned to the LORD, and said, "Alas, this people has committed a great sin, and they have made a god of gold for themselves. But now, if You will, forgive their sin--and if not, please blot me out from Your book which You have written!"
The LORD said to Moses, "Whoever has sinned against Me, I will blot him out of My book. But go now, lead the people where I told you. Behold, My angel shall go before you; nevertheless in the day when I punish, I will punish them for their sin."