The Torah tells us of two offerings when parts of a sacrificed animal are separated from the rest, and then burnt outside:
The flesh and the skin were consumed in fire outside the camp. (Lev. 9:11)
The rest of the flesh of the bull, its hide, and its dung shall be put to the fire outside the camp; it is a sin offering.(Ex. 29:14)
Why is this done – and why only in these two cases?
The answer seems apparent enough. These are both sin offerings. Other offerings are not designed to make us suffer – they are all different ways to connect to G-d, and they do not necessarily require that we feel bad about ourselves. Instead, other (non-sin) offerings are ways to grow a relationship with G-d.
But a sin offering is for when a person is supposed to feel regret and loss, resolving to not committing that sin again. The first named sin in the Torah is that of Cain – G-d warns Cain that, though “sin crouches at the door,” it is within Cain’s ability to master it. Cain fails to do so – teaching us that at the root of sin is the desire to surrender ourselves to our anger, our desire to give into our basest instincts, using violence to dominate. Sin is loss of self control. In the worst case, that of Cain, the ultimate sin is to murder someone.
Which means that an offering that is meant to atone for sin must speak to us at the most fundamental level; we have to feel as though we are suffering in kind for the sin we have committed. We have to try to understand what it would be like to be on the other side of Cain’s rage. And we do that by identifying with the offering.
Herein lies the challenge: If we sacrifice a calf or an ox, we see them as animals, not similar to people. But on the inside, people look much more like animals than they do on the outside – we share all the same organs. And so, unlike every other offering in the Torah, the sin offering requires that the parts of the animal that make it recognizably not human, should be removed and burnt elsewhere, leaving the offeror a view of an offering that they can see as being more – rather than less – human.
[An @iwe, @susanquinn, @blessedblacksmith, @kidcoder and @eliyahumasinter tidbit]