Parashas Ki Sisa · Passuk 34:19
Torah Temimah points to classical source on this unit (verified).
English: “Every first issue of the womb is Mine” — the firstborn belongs to Hashem.
Derash on firstborn of womb and flock belonging to Hashem.
Every first issue of the womb is Mine, and every firstborn male of your livestock, whether ox or sheep.