As this passage shows, the Passover lamb did much more than just provide blood - it was a distinctive meal. God begins with instructions to ensure that every person would have enough, but also that it would not be wasted. He continues with specific details, including when it should be eaten, how it should be prepared, what should be eaten with it, what should be done with the remains, and even how the Israelites should be dressed. The bulk of God's instructions concern the specially prepared lamb they were to eat. The repeated emphasis in both Old and New Testaments is on the eating of the Passover (Exodus 12:43, 48; 34:25; Numbers 9:11; II Chronicles 30:18; Ezra 6:21; Matthew 26:17, 26; Mark 14:12, 14, 22; Luke 22:8, 11, 15, 19; John 13:2; I Corinthians 11:23-26; see John 6:31-58), and this begins to set it apart from a sin offering, which was not generally available for eating.
A second difference is who was allowed to eat each sacrifice. The Passover was a meal shared by a circumcised household, while in the sin offering, only the males among the priests ate portions of it (Leviticus 6:26), and only in two cases. The sin offering is divided into four categories, according to who had committed the sin, whether a priest (verses 3-12), the whole congregation (verses 13-21), a leader of the people (verses 22-26), or an individual (verses 27-31). In the case of a priest or the whole congregation, the priest offered part of the animal on the altar as God's portion, and then he burned the remainder outside the camp (Leviticus 4:8-12, 19-21; 6:30), and thus, nothing was eaten by the priest. The priests could only eat a sin offering for a leader or another individual.
This teaches that while the priest could receive a portion for his service in performing the work of the sin offering in some cases - that is, when the offering was for the sin of a leader or other individual - he could not receive any portion when it was for the sin of the priesthood or the congregation, of which he was a part. In other words, he was not to eat of the offering for sins he had a part in. In addition, God did not allot any of the sin offering for the one making the offering. When we apply this to the Passover, it gives us a third reason why it was not a sin offering: In type, it would signify each household benefitting from - being fed by - the sins they had committed, which is entirely contrary to the divine pattern.
As mentioned, only the priests could eat of the sin offering, and only when it was for a leader or an individual (other than a priest). Of the four scenarios, a household (being a group) is the most like a congregational offering, and in that scenario, none of the sacrifice was to be eaten. What wasn't put on the alter was burned outside the camp.
