Parashas Behar · Aliyah 1 · Passuk 25:08
Chabad.org — English translation + Rashi
Torah Temimah cites Sifra (Torat Kohanim).
English: “And they shall be for you.” It was taught: From where do we know that one must count the years of the shevu’a? The verse says “and they shall be for you the days of the seven Sabbaths of years.” And from where do we know that one must count the years of the Yovel? The verse says “and they shall be for you forty-nine years.”
Classical derasha (Sifra).
One must count both the seven-year cycles and the forty-nine years leading to the Yovel.