Reference for Pesachim 33:4

ושמואל אמר לא אישתבש כהני חמישי בקדש בעא מינייהו ואמרו ליה טהור

But Samuel maintained, The priests did not err'; he asked them about a fifth degree in respect of holy foodstuffs, and they answered him, It is clean. As for Rab, it is well: hence four are written, 'bread, pottage, wine, and oil'; but according to Samuel, whence does he know five? - Is it then written, 'and his skirt<span class="x" onmousemove="('comment',' I.e., the sherez which was in his skirt.');">⁴</span>

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