Translation: “This is the law of the meal-offering” — one law for all of them, to require oil and frankincense as stated in the matter. One might think only an Israelite’s mincha (from which a kometz is taken) requires oil and frankincense; whence the mincha of kohanim which is entirely burnt? Scripture says “torah” — a single law.
In Sifra / in context: The word תורת generalizes the requirements of oil and frankincense to every species of mincha, including those of kohanim.
Middah: R’ Yishmael #1 (קל וחומר / generalization from the wording) / Custom.