Matthew Henry Commentary Exodus 32:21-29

"And Moses said unto Aaron, What did this people unto thee, that thou hast brought a great sin upon them? And Aaron said, Let not the anger of my lord wax hot: thou knowest the people, that they are [set] on evil. For they said unto me, Make us gods, which shall go before us; for as for this Moses, the man that brought us up out of the land of Egypt, we know not what is become of him. And I said unto them, Whosoever hath any gold, let them break it off: so they gave it me; and I cast it into the fire, and there came out this calf. And when Moses saw that the people were broken loose, (for Aaron had let them loose for a derision among their enemies,) then Moses stood in the gate of the camp, and said, Whoso is on Jehovah`s side, [let him come] unto me. And all the sons of Levi gathered themselves together unto him. And he said unto them, Thus saith Jehovah, the God of Israel, Put ye every man his sword upon his thigh, and go to and fro from gate to gate throughout the camp, and slay every man his brother, and every man his companion, and every man his neighbor. And the sons of Levi did according to the word of Moses: and there fell of the people that day about three thousand men. And Moses said, Consecrate yourselves to-day to Jehovah, yea, every man against his son, and against his brother; that he may bestow upon you a blessing this day." — Exodus 32:21-29 (ASV)

No wise man ever made a more frivolous and foolish excuse than that of Aaron. We must never be drawn into sin by anything people can say or do to us, for people can only 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 misrepresenting it, but by punishing it.

The Levites were to slay the ringleaders in this wickedness; yet no one was executed except those who openly stood out.

Those who persist in sin are marked for ruin: those who in the morning were shouting and dancing, before night were dying. The Lord's judgments sometimes bring such sudden changes upon sinners who are secure and jovial in their sin.