Yoma 56a and Yoma 56b, figuring out R. Yehudah’s view of there being only one table for blood in the Temple, his view of bererah, later events determining what occurred for halachic reasons, our desire to help the Kohen Gadol not make errors during the service, and how that affects the hazan‘s recitation of the Yom Kippur service on Yom Kippur.
