Midrash for Chullin 264:50
ולית הלכתא כוותיה
A priest who does not believe in the [Temple] service<span class="x" onmousemove="('comment',' As a divine institution.');"><sup>25</sup></span>
Sifrei Devarim
"from the people": and not from others (i.e., gentiles), and not from his fellow Cohanim.
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