If a Chayah (which one is not obligated to feed), is permitted to eat, why does the Torah see fit to add "Beheimah" (which one is)?
Rashi and Ramban (both citing the Sifra): The Torah is comparing Beheimah to Chayah, in that, as long as the Chayah is able to find any particular species in the field, one is permitted to feed one's Beheimah in the house that species. 1
Rashi (in Shabbos, 68a): The Pasuk teaches us that the laws of Sh'mitah extend to animal fodder.
Ramban: But once it is no longer available in the field, one is obligated to clear it out of the house and declare it Hefker, a procedure that the Chachamim call 'Bi'ur Shevi'is' (See Ramban, who elaborates at length).
What are the implications of the words "Asher be'Artzecha"?
Shevi'is, 6:4: It implies that one may not take Sh'mitah produce out of Eretz Yisrael in order to feed one's animals in Churz la'Aretz.
Why does the Torah insert the word "Kol Tevu'asah"?
Oznayim la'Torah (citing a Tosefta: To teach us that, although it is forbidden to feed an animal human food, 3 if an animal wants to est a fig in the Sh'mitah, we are not obligated to stop it.
Why does the Torah nsert the word "Le'echol"? Why does it not include Beheimah and Chayah in the previous Pasuk?