Parashas Bo · Passuk 12:5
Chabad.org — English translation + Rashi
Torah Temimah points to Mechilta (verified).
Sefaria — Exodus 12:5
Sefaria — Mechilta
English: “From the sheep and from the goats” — might one take from both together as one? Therefore [we learn] from the sheep or from the goats.
In context: See the cited source for the full section.
Kal vachomer / limiting (Mekhilta) — middah of R’ Yishmael’s 13.
The Pesach is taken from sheep or from goats, one species per offering.