In Bamidbar 8-8 it says that as part of the Taharas Haleviim, a פר should be brought but we are not told what type of korban it is. In the very same pasuk we are told to bring a second פר for a חטאת. Why does the Torah keep it a secret what the first פר is for [Rashi let us in on the secret but that doesn't explain why the pasuk itself didn't tell us]? Only a few psukim later we are told that one פר is a חטאת and the other [mentioned second even though earlier it was first] an עולה.
אתמהה!!
Here is a shiur on the pasuk [even though the question isn't answered because I don't know the answer:-)].
