The Medrash Tanchuma says that as the Bnei Yisroel were making the Eigel, Hashem was engraving the Luchos. The next day Moshe broke the luchos because of the Eigel, why would Hashem engrave them as they were making the Eigel? Moshe told Bnei Levi to kill all those involved in the Eigel even their own family. Why didn’t Moshe do likewise and kill his brother Aharon who made the Eigel?
The Bechorim lost the Kehuna because of the Cheit HaEigel. Why did Aharon become Kohen Gadol? Rav Isaac Sher explains that making the Eigel was not an aveira…. WHAT???
He explains.. There was an ongoing dispute between Moshe Rabbeinu and Klal Yisroel. The people believed that Moshe had Godly power to do what he wanted and therefore made many demands of him. Moshe always tried to explain that he was a powerless intermediary who only does Hashem’s will. When they thought Moshe died they came to Aharon and said, instead of choosing a new leader in whom the people can err once again into believing that he has his own power, let Hashem himself lead us. How then would they know without an intermediary if Hashem is happy with them or not?
They would make an object that would serve as an indicator of Hashem’s satisfaction just like the keruvim faced each other when Bnei Yisroel were doing mitzvos and turned away from each other when they were not.
This was the pure intention behind of the Eigel. Aharon agreed to this logic as he specifically said “Chag L’Hashem Mochor”; let’s make a party for Hashem tomorrow.
Hashem himself had no objection and he continued to engrave the Luchos. The aveira occurred the next day when they began to act inappropriately during the festivities. It was the ruckus from the partying that Moshe heard that caused him to break the luchos.
This, says Rav Yitschok was not Aharon’s aveira and he eventually went on to become Kohen Gadol.
