Parashas Tetzaveh · Passuk 29:9
Chabad.org — English translation + Rashi
Torah Temimah points to Zevachim 17b (verified).
Sefaria — Exodus 29:9
Sefaria — Zevachim 17b
E-Daf — Zevachim 17b
English: A baraita derives from “and it shall be for them priesthood” that a priest who performs service while missing required garments has invalidated his service. When their garments are upon them, their priesthood is upon them; when their garments are not upon them, their priesthood is not upon them.
On the daf / in context: See the cited source for the full section.
Derash on the verse.
The required priestly garments are an integral condition of priestly status for service; lacking them invalidates the service.