יי spoke to Moses, “Hurry down, for your people, whom you brought out of the land of Egypt, have acted basely. They have been quick to turn aside from the way that I enjoined upon them. They have made themselves a molten calf and bowed low to it and sacrificed to it, saying: ‘This is your god, O Israel, who brought you out of the land of Egypt!’”
יי further said to Moses, “I see that this is a stiffnecked people. Now, let Me be, that My anger may blaze forth against them and that I may destroy them, and make of you a great nation.”
But Moses implored his God יי, saying, “Let not Your anger, יי, blaze forth against Your people, whom You delivered from the land of Egypt with great power and with a mighty hand. Let not the Egyptians say, ‘It was with evil intent that he delivered them, only to kill them off in the mountains and annihilate them from the face of the earth.’ Turn from Your blazing anger, and renounce the plan to punish Your people."
Moses saw that the people were out of control—since Aaron had let them get out of control—so that they were a menace to any who might oppose them. Moses stood up in the gate of the camp and said, “Whoever is for יי, come here!” And all the men of Levi rallied to him.
He said to them, “Thus says יי, the God of Israel: Each of you put sword on thigh, go back and forth from gate to gate throughout the camp, and slay sibling, neighbor, and kin.”
The men of Levi did as Moses had bidden; and some three thousand of the people fell that day.
And Moses said, “Dedicate yourselves to יי this day—for each of you has been against blood relations—that [God] may bestow a blessing upon you today.”