And Moses said to Aaron, "What did this people do to you that you have brought such a great sin upon them?" And Aaron said, "Let not the anger of my lord burn hot. You know the people, that they are set on evil. For they said to me, 'Make us gods who shall go before us. 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.' So I said to them, 'Let any who have gold take it off.' So they gave it to me, and I threw it into the fire, and out came this calf." And when Moses saw that the people had broken loose (for Aaron had let them break loose, to the derision of their enemies), then Moses stood in the gate of the camp and said, "Who is on the LORD's side? Come to me." And all the sons of Levi gathered around him. And he said to them, "Thus says the LORD God of Israel, 'Put your sword on your side each of you, and go to and fro from gate to gate throughout the camp, and each of you kill his brother and his companion and his neighbor.'" And the sons of Levi did according to the word of Moses. And that day about three thousand men of the people fell. And Moses said, "Today you have been ordained for the service of the LORD, each one at the cost of his son and of his brother, so that he might bestow a blessing upon you this day."
Exodus 32:21-29
Moses loses no time in dealing with the situation. First Aaron, as the fabricator of the idol, then the idolaters themselves, are summarily dealt with. The fundamental and woefully pathetic weakness of Aaron is exposed here (22-24), and all the more graphically alongside the moral and spiritual stature of his brother. Did he really think that such inane excuses could possibly carry weight with Moses, let alone with God? It is a measure of the ineffectualness of Aaron's character that the people should have ever approached him in the first place about making the calf or that he should have even for a moment countenanced their request. Moses' dealing with the people was grim and thorough, but not too grim if we take 'so great a sin' (21) as seriously as God took it. George Philip writes: 'In every work or movement of defection there are two distinguishable groups which need to be dealt with differently. There are ringleaders, and those who are beguiled and enticed. When the disciplinary word and work is operative, those whose hearts are genuine, though beguiled, are quick to see their error, and hurry back to the side of God. This they must do in a clearly defined way, by taking their place at the side of God's man .... Then, the ringleaders who refuse to stop their idolatry are to be rooted out and put to the sword as a matter of policy so that, the evil root being destroyed, the poison will no longer spread among the people'. This is the force of Moses' resounding challenge in 26. He in effect excommunicated the entire camp by standing in the gate, and summoned them to form a new band of consecrated people (cf Hebrews 13:12, 13). There must be a clean break with idolatry, before there could be any further possibility of going on with the Lord.