Yoma 51 a, b

We continue yesterday's conversation about substitutions, sacrifices and related halachot.

First, the Gemara explains that substitution is one category where there are no differences between different substitutions.  With sacrifices, however, halacha regarding the firstborn and the animal tithe are different from other offerings. We cannot understand a general principal from this type of category.  A note teaches us that these particular tithes are consecrated in advance (in utero and as the tenth animal counted, even if it has a blemish).  These offerings are never redeemed, sheared or worked.

In trying to decode a baraita, the rabbis have been arguing about whether or not a bull can be substituted if it dies part way through the ceremony. Now Rav Sheshet suggests that that baraita referred to the High Priest's ram, and thus the ram of Aaron and the Paschal offering is discussed (rather than the bull and the Yom Kippur offering).  Rav Sheshet argues that we do not slaughter the Korban Pesach for an individual but for a group; the second Pesach offering overrides Shabbat but does not override ritual impurity, as in the baraita's commentary.  Rav Huna, son of Rav Yehoshua and Rava speak further about the implications of the halachot of the second Pesach.  They look at performance of mitzvot in a state of ritual impurity under specific conditions.

Rabbi Elazar had asked earlier about whether a High Priest can make a substitution for his bull. This would require the priests to gain atonement because they were 'full partners' in the offering. Even if this baraita helps us understand what Aaron did in his own circumstances, it does not solve Rabbi Elazar's question.

A new Mishnah tells us that the High Priest would then walk west in the Sanctuary to the curtain at the Holy of Holies.  It explains that the curtain separates the Sanctuary from the Holy of Holies by one cubit of space.  The Gemara wonders whether this was the case in both Temples.  Part of their consideration is the layout of each Temple.