TT #151 · Parshas Tazria · Aliyah 3 · Passuk 18
English: When the flesh has a boil on its skin and it heals.
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:18
Sifra (Toras Kohanim).
Sifra — Vayikra 13, Midrash Sefer
English: “Boil”—I know only a boil that arose on its own. From where do we include a lesion caused by wood, stone, olive-press residue, the hot springs of Tiberias, or anything else not caused by fire? Scripture repeats “boil,” broadening the category.
Textual derivation
The Sifra expands “boil” to include lesions caused by wood, stone, olive-press residue, and the hot springs of Tiberias, while distinguishing non-fire causes from the separate burn category.