Whoever is on the Lord’s side— come to me!”

Now when the people saw that Moses delayed coming down from the mountain, the people gathered together to Aaron, and said to him, “Come, make us gods that shall go before us; for as for this Moses, the man who brought us up out of the land of Egypt, we do not know what has become of him.” And Aaron said to them, “Break off the golden earrings which are in the ears of your wives, your sons, and your daughters, and bring them to me.” And he received the gold from their hand, and he fashioned it with an engraving tool, and made a molded calf. Then they said, “This is your god, O Israel, that brought you out of the land of Egypt!” And the Lord said to Moses, “Go, get down! For your people whom you brought out of the land of Egypt have corrupted themselves. They have turned aside quickly out of the way which I commanded them. They have made themselves a molded calf, and worshiped it and sacrificed to it, and said, ‘This is your god, O Israel, that brought you out of the land of Egypt!’ ” And the Lord said to Moses, “........ And I will make of you a great nation.” And Moses turned and went down from the mountain, and the two tablets of the Testimony were in his hand. The tablets were written on both sides; on the one side and on the other they were written. Now when Moses saw that the people were  unrestrained (for Aaron had not restrained them, to their shame among their enemies), then 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. And 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.’ ”
Exodus 32:1-2,4,7-10,15,25-27 - NKJV