Parashas Bo · Shemos 12:15 · TT note 10
Torah Temimah on Shemos 12:15, note 10 (on אַךְ בַּיּוֹם הָרִאשׁוֹן תַּשְׁבִּיתוּ) points to Pesachim 5a.
Sefaria — Exodus 12:15
Sefaria — Torah Temimah on Exodus 12:15
Sefaria — Pesachim 5a
E-Daf — Pesachim 5a
English: It was taught: “But on the first day you shall remove se’or from your houses” — from erev Yom Tov. Or is it only on Yom Tov itself? Scripture says: “You shall not slaughter My offering’s blood over chametz” — do not slaughter the Pesach while chametz still exists.
Timing of hashbasah: erev Yom Tov, proven from the ban on slaughtering Pesach over remaining chametz.
Se’or must be removed before Yom Tov begins, so that the Pesach is not slaughtered while chametz is still present.