Reference for Zevachim 33:4

אימא תנהו ענין לקורח קרחה ולמשחית פאת זקן

since this cannot refer to an unclean [priest], for [his prohibition] is deduced from, That they separate themselves,<span class="x" onmousemove="('comment',' Ibid. XXII, 2; that verse forbids an unclean priest to officiate.');">⁴</span> apply it to a tebul yom.<span class="x" onmousemove="('comment',' As intimating that he too must not officiate, and if he does, he 'profanes', i.e. , disqualifies the sacrifice.');">⁵</span>

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