Midrash su Levitico 25:8

1) (Vayikra 25:8) ("And you shall count for yourself seven Sabbaths of years, seven years, seven times; and they shall be for you, the days of the seven Sabbaths of years, forty-nine years.") "And you shall count for yourself": in beth-din": I might think seven Sabbaths of days, i.e., seven weeks; it is, therefore, written "seven Sabbaths of years." If "seven Sabbaths of years" (alone were written), I might think that he counts seven shemitoth one after the other and then declares Yovel. It is, therefore, written "seven years, seven times." (i.e., in forty-nine years, seven shemitoth seven times.) Both verses, then, are needed; if not, we would not know (the halachah.)

2) And whence is it derived that we count the years of the seven (shemitoth, e.g., Today marks the first year to shemitah")? From "the days of the seven Sabbaths of years." Whence is it derived that we count the years of Yovel? From "forty-nine years." Whence do we derive that shemitah is observed even if Yovel is not observed, (as when the ten tribes were exiled)? From "seven Sabbaths of years." And whence is it derived that Yovel is observed even if shemitah is not observed, (as in the instance of their returning to Eretz Yisrael at the end of fifty years)? From "forty-nine years." These are the words of R. Yehudah. And the sages say: Shevi'ith is observed even if Yovel is not observed; but Yovel is not observed unless accompanied by Shevi'ith.

8) (Vayikra 25:8) ("And to your beast and to the animal which is in your land shall be all its produce to eat.") What is the intent of this ("your beast")? If an animal, which is not yours, may eat, how much more so a beast, which is yours! If so, I would say: Let him bring the beast (into the house) and let him eat always! And how would I satisfy the removal of fruit (from the house) on shevi'ith? With the fruits of man. And a beast would eat always. Now that it is written "and to your beast and to the animal," the beast is being compared to the animal, viz.: So long as the animal eats in the field, the beast eats in the house; if it has ended for the animal in the field, "end it" (i.e., remove it) from your beast in the house.