Parashas Acharei Mos · Passuk 16:04
Chabad.org — English translation + Rashi
Torah Temima points to Zevachim 19b.
English: If a Kohen Gadol did not immerse or sanctify between garment and garment or between service and service, and he served, his service is valid — for Scripture says “and put them on”: donning is indispensable, and nothing else is indispensable.
Donning is me’akev
Wearing the correct garments is essential; missing an intervening tevilah or kiddush does not invalidate the service after the fact.