The Talmud Bavli in Chagiga 12b mentions that there is a place where the angel Michael offers korbanos to Hashem. The Chiddushei Aggados commentary (can be seen on the above link on Sefaria) states a classic that I've seen in earlier sources as well -- that Michael sacrifices the souls of tzaddikim.
I wanted to know what that means exactly. It's clearly a symbolic image, so what does it mean to "offer the soul of the tzaddik as a korban?
Also, I understand the reason why Michael does it (as opposed to any other malach) is because he functions like a kohen gadol in the realm of the angels (which the Chiddushei Aggados also says). However, why is the help of a malach altogether needed -- wouldn't we consider the entire life of a tzaddik exactly that, -- a sacrifice of himself to Hashem, that is performed by the person himself?
Thank you very much.