Parashas Bo · Shemos 12:5 · TT note 4
Torah Temimah on Shemos 12:5, note 4 (on יִהְיֶה לָכֶם) points to Zevachim 25b.
Sefaria — Exodus 12:5
Sefaria — Torah Temimah on Exodus 12:5
Sefaria — Zevachim 25b
E-Daf — Zevachim 25b
English: “A perfect male, a year old” — that it be perfect and a year old at the time of slaughter; from where [do we know] that the same applies also at receiving, carrying, and sprinkling? Therefore it says “it shall be for you” — all of its states must be only while unblemished and a year old.
Extension from יִהְיֶה לָכֶם: the age and unblemished status apply through all the avodot, not only slaughter.
If the animal becomes a year-and-a-day or develops a blemish between slaughter and the later avodot, those avodot are invalid.