1)
Why did Moshe burn and grind up the Egel and cast the ashes to the river?
1.
Ramban: It was to make Yisrael drink the water like Sotos. He did not mention this here, in order not to overly embarrass them.
2.
Da'as Zekenim, Rosh: It was lest they benefit from (Hadar Zekenim
