Parashas Behar · Aliyah 1 · Passuk 25:04
Chabad.org — English translation + Rashi
Torah Temimah cites Sifra (Torat Kohanim).
English: “And in the seventh year.” It was taught: From where do we know that the thirty days before Rosh Hashanah are regarded as the entire year? The verse says “and in the seventh year.” From here they said: regarding benos shuach [a species of fig], the seventh year of theirs is the second [year of the cycle], because they produce over three years.
Classical derasha (Sifra).
Thirty days before Rosh Hashanah are treated as the entire year for certain Shemittah-related determinations (e.g., the status of benos shuach figs).