See also this attempt at defending Aharon
Parshat Ki Tisa
by Rabbi Avi Billet
Looking objectively at the depiction of the creation of the Golden Calf, it is quite hard to understand the role Aharon plays. Is he guilty of something really really bad? Is he a manipulated victim? Was he coerced? Was he just in the wrong place at the wrong time?
What is clear is that on account of Moshe's delayed return, Aharon is approached and told to make "something" to replace Moshe as leader. Aharon instructs the people to get the earrings of their family members – children and wives – and with the earrings the men bring back (which seem to be their own earrings), he has a mold or model golden calf fashioned. Either he does it personally, or he has someone else do it. Upon seeing how some of the people related to the calf, Aharon builds a mizbe'ach and announces "There will be a festival to God tomorrow!" – God, of course, being the Tetragrammaton – God's four letter name of יקוק.
What is also clear is that Aharon never referred to this calf as a God, and he certainly never participated in any festivities or worshipping of the calf.
What, then, was his role? Why does Moshe become so upset with him?
Ralbag posits that Aharon was doing only one thing: stalling.
He asked for the jewels of family members, assuming they would not give their jewelry up easily. He began to mold a model of the calf to delay the actual building of what the people were asking for.
When Moshe still did not show, Aharon began building a mizbe'ach. This takes time. And when it was finished, instead of inaugurating it right away as is commonly done, Aharon had the brilliant idea to buy more time through delaying until "tomorrow." That the people took the initiative on their own the following morning, when they saw Aharon was not leading any festivities, is their problem. Aharon could no longer fight off the mob mentality that had overtaken the minds of those who were smitten by the perception of what the Golden Calf would do for them.
Abravanel observes that we really do not know when the people first approached Aharon. At the end of Mishpatim Moshe went up, with no provisions and no foreseeable means of nutrition, to be on the mountain for an undetermined amount of time. Up until then, every time he went up he came down the same day. (See his ups and downs in Shmot 19).
Did they approach Aharon after 3 days? A week? Two weeks? Just because the tale of the creation of the Golden Calf pans out in six verses does not mean it did not take two weeks of negotiating and staying the crowd! That the Torah told us Moshe went up for 40 days and nights (24:18) does not indicate the people, or even Moshe, were aware he'd be away that long, or for any specific amount of time. It is possible Moshe might have stayed longer, had he not been sent packing on account of the wayward actions of the people down below.
And if Hur had been killed (24:14 indicates he and Aharon were in charge and as Hur does not appear in our tale, the Rabbis said he had been killed by the mob), Aharon has real cause to respond to their requests, to indicate he is working with them, before he is taken down as well. Ibn Ezra raises one person's opinion (he does not quote from whom) that Aharon felt the need to avoid losing his life in order to save as many people as possible. Were he to die, things would go out of control quickly, and many more people would succumb to the peer-pressure and join the ranks of the Golden-Calf-ers – 3,000 of whom were killed in its aftermath.
Therefore the Abravanel spells out in great details how Aharon was delaying. He took the time to fashion a small model of a golden calf (the choice of calf versus lamb has to do with the lamb being Aries, the god of Egypt, and the calf being Taurus, the next Zodiac sign, as the god of Egypt had been defeated by the God of Israel). In turn, the model would be copied in a much larger version, which would take a day or two to fashion. And, frankly, Aharon indicated that such an "important" item could not be completed without the stamp of Moshe! This would further cause them to wait.
That he wanted everything to be done right would also play into why he insisted on building the mizbe'ach himself! He was hoping that in all the delayed efforts, the people would take a step back and realize they were pursuing a worthless goal of a meaningless symbol to replace Moshe as the leader.
He said the "Festival would be for Hashem tomorrow" hoping A. that God would hear and tell Moshe to scoot on down to nip the rebellion in the bud; and B. that the masses would understand that anything they were doing was for the sake of Hashem in Heaven. Unfortunately, neither plan worked and Moshe was only told to leave after the party had started, on account of the boors who did not understand Aharon's intent when utilizing God's name in anticipation of any celebration.
When Moshe emerges he becomes so upset with his brother because Aharon played a role in bringing about the sin the people committed. It could be Aharon's intentions were honorable: play the role, cater to them in a way they think you're on their side while you delay as much as you can, hope and pray that Moshe will come down and set everything right. But honorable intentions don't always bring about positive results. Just think about Lot's daughters.
Are we to understand that delay tactics don't work, and a person must take a stand to do what's right at the outset, even at the cost of one's life? Not at all. Sometimes delaying a little while allows a sensible solution to play itself out. (Sometimes it doesn't – see Samuel I 13:6-14) From Moshe's perspective, however, the stakes were too high and his brother faltered at what could have been his finest hour.
In an immediate and direct sense, it does not seem Aharon is punished for any idolatry component of the Golden Calf. He does not lose his life and he does not lose the right to be the High Priest who brings about forgiveness for the people on Yom Kippur. Therefore I do not think it is our place to be too critical of Aharon.
What might any one of us have done were we in his place? It is very hard to say.