Parashas Behar · Aliyah 6 · Passuk 25:45
Chabad.org — English translation + Rashi
Torah Temimah cites Sifra (Torat Kohanim).
English: “And also from the children of the residents.” This teaches that one may acquire from the resident strangers who dwell among you.
Classical derasha (Sifra).
Children of resident non-Jews born in the Land may also be acquired as permanent slaves and become a holding.