The Torah prohibits two types of situations in which a person would eat food from a korban (offering). Number one is a situation in which the person eats Kodesh (consecrated food) that became Tameh (ritually impure). The penalty for that would be Malkut, or lashes. Another situation would be where a Tameh person ate Kodesh that was Tahor (pure). The penalty would be Karet (being cut off) if it was done intentionally, and a korban chatat (sin offering) if it was done unintentionally.
The Mishnah says, if a Tameh person ate either Kodesh that was Tameh or Kodesh that was Tahor, he is Chayav, liable for Karet, for violating the Isur (prohibition) against a Tameh person eating Kodesh. Rabbi Yosei HaGelili says, “Only in a situation where a Tameh person ate Kodesh that was Tahor” is he liable for Karet. He agrees to that. But what about a situation where a Tameh person ate Tameh? If a Tameh person ate Kodesh that was Tameh, he would not be liable for Karet, because he only ate something that was Tameh and was already forbidden to be eaten.
So, in other words, the person gets lashes when he eats Kodesh that becomes Tameh. That’s what we said at the beginning of this Mishnah: if a person ate food—Kodesh that was Tameh, a korban that was Tameh—he gets Malkut. So, in the situation where he was Tameh but the food was Tameh as well, Rabbi Yosei HaGelili says he wouldn’t be liable for Karet as a Tameh person who ate Kodesh, because the food was Tameh. And therefore, we say that you go by the food. If a person ate Kodesh that was Tameh, he receives Malkut.
The Chachamim (the Sages) understood that Rabbi Yosei HaGelili says the Torah’s prohibition against a Tameh person eating Kodesh applies only to Kodesh that was Tahor. So they are going to answer him with an inconsistency in his opinion. So, Rabbi Yosei HaGelili says that you agree that a person is Karet for eating Kodesh that became Tameh because you have to touch it in order to eat it. So the same should apply even in a situation of Kodesh that became Tameh before he touched it. There should be consistent cases. If you’re telling me that when he was Tahor and then he touched it and ate it, a person would be liable for Karet, then he would be liable for Karet even if he touched it before he was eating it. So they point out an inconsistency in the opinion of Rabbi Yosei HaGelili.
Now, we’ll say the halakha (Jewish law) according to all views for a Tahor person who eats Kodesh that is Tameh—a Kodesh that was Tameh. Patur, he’s not liable for Karet, only for Malkut, like we mentioned. A person is liable for Karet for eating Kodesh in a state of Tuma'ah (ritual impurity) only when the Tuma'ah is on the person’s body, not because the food was Tameh, and not because the korban was Tameh. Only if it’s a Tameh person eating Kodesh. But if the food was Tameh and a regular pure person was eating it, he would not be Chayav Karet in that situation. He would have to receive Malkut; he would receive lashes.