21 And Moses said to Aaron, "What did this people do to you that you have brought so great a sin upon them?" 22 So Aaron said, "Do not let the anger of my lord become hot. You know the people, that they are set on evil. 23 For 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.' 24 And 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." 25 Now when Moses saw that the people were unrestrained (for Aaron had not restrained them, to their shame among their enemies), 26 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. 27 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.' " 28 So the sons of Levi did according to the word of Moses. And about three thousand men of the people fell that day. 29 Then Moses said, "Consecrate yourselves today to the Lord, that He may bestow on you a blessing this day, for every man has opposed his son and his brother."
Matthew Henry's Commentary on Exodus 32:21-29
Commentary on Exodus 32:21-29
(Read Exodus 32:21-29)
Never did any wise man make a more frivolous and foolish excuse than that of Aaron. We must never be drawn into sin by any thing man can say or do to us; for men can but tempt us to sin, they cannot force us. The approach of Moses turned the dancing into trembling. They were exposed to shame by their sin. The course Moses took to roll away this reproach, was, not by concealing the sin, or putting any false colour upon it, but by punishing it. The Levites were to slay the ringleaders in this wickedness; yet none were executed but those who openly stood forth. Those are marked for ruin who persist in sin: those who in the morning were shouting and dancing, before night were dying. Such sudden changes do the judgments of the Lord sometimes make with sinners that are secure and jovial in their sin.