Parashas Behar · Aliyah 2 · Passuk 25:16
Chabad.org — English translation + Rashi
Torah Temimah cites Sifra (Torat Kohanim).
English: “According to the multitude of the years you shall increase its purchase price.” When there are many years, increase the price; “and according to the fewness of the years you shall diminish its purchase price” — when there are few years, diminish the price.
Classical derasha (Sifra).
The sale price of a field must be adjusted proportionally to the number of years remaining until Yovel.