Parashas Bo · Shemos 12:4 · TT note 3
Torah Temimah on Shemos 12:4, note 3 (on מִהְיוֹת מִשֶּׂה) points to Pesachim 90a.
Sefaria — Exodus 12:4
Sefaria — Torah Temimah on Exodus 12:4
Sefaria — Pesachim 90a
E-Daf — Pesachim 90a
English: It was taught: “If the household is too small from being of a lamb” — revive it from the lamb. [One may take money] for the sake of eating, but not for the sake of ordinary purchase. … The Rabbis hold: the Torah said “from being of a lamb” — revive the lamb [by using proceeds for Pesach needs such as wood for roasting, matzah and maror].
Derash of מִהְיוֹת מִשֶּׂה as “revive the lamb” — proceeds from selling a share may support the offering’s needs.
One may enroll others on one’s Pesach and use the money for wood, matzah and maror (needs of the meal), but not for ordinary garments.