Sacrifices and Holiness
The Torah gives various punishments for various violations of its laws. The “Karet” penalty is considered very severe as it is administered by the Heavenly court.
It could involve dying young, or witnessing the death of one’s children, G-d forbid. It could also involve being “cut off” from the Jewish people, where one might lose his share in Olam Haba, the next world.
It is surprising that this was the penalty mentioned in the Torah for שחוטי חוץ, slaughtering an animal outside of its designated area. In the desert, one was not permitted to eat meat at all, unless part of the animal was offered as a sacrifice. If one disobeyed, it was punishable with “Karet.”
When the Temple was in existence, this prohibition applied in a slightly different manner. It referred to one who offered a sacrifice on his own altar, and did not offer it in Jerusalem. This, too, was considered a severe enough violation, that it was in the “Karet” category.
The question was why was this considered an infraction on the level of eating Chametz on Pesach, or eating on Yom Kippur?
The theme of these two Parshiot of Acharei Mot and Kedoshim, that are normally read together, is achieving holiness. This potential for holiness is unique only to the Jewish people. The Gentile can be righteous, but the Jew acquires holiness through the observance of the Mitzvot.
The Jews were on a very high level in the desert. They ate the Manna and were protected by the Clouds of Glory. The consumption of meat, that had an animalistic aspect to it, needed to be elevated, by offering a portion as a sacrifice.
The offering of a private sacrifice without bringing it to the Temple, was a disconnection from the dwelling place of the Divine Presence. Such a sacrifice was personal in nature. It lacked the sanctity and elevation that the Temple provided.
The warning of Karet in these two instances was that we must take great care to avoid getting off course from our ultimate mission as Jews. We must never minimize the special destiny of the Jewish people, when we were told at Mount Sinai, that we were to be a ממלכת כהנים וגוי קדוש, “A kingdom of priests and a holy nation.” We must never allow ourselves to divert from our mission, and we must always be proud to be Jews.