Parashas Behar · Aliyah 1 · Passuk 25:06
Chabad.org — English translation + Rashi
Torah Temimah cites Sifra (Torat Kohanim).
English: “And the Sabbath of the land shall be for you.” From that which rests you may eat; you may not eat from that which was guarded.
Classical derasha (Sifra).
One may eat only of produce that grew of its own accord (the “resting” of the land); one may not eat of produce that was guarded or protected in violation of Shemittah.