(Exodus 22:30) "And men of holiness shall you be to me": R. Yishmael says: When you are holy, you are Mine. Issi b. Yehudah says: When the Holy One Blessed be He originates a mitzvah for Israel, He adds holiness to them. Issi b. Guriah says: It is written here (Devarim 14:21) "holy" ("for a holy people are you … You shall not cook a kid in its mother's milk"), and, elsewhere (Exodus, Ibid.) "holiness." Just as here ("a kid, etc.") the prohibition is eating, so, there, ("treifah") the prohibition is eating.