Reference for Niddah 118:21

מה לי א"ר מאיר

is involved, but where a double doubt<span class="x" onmousemove="('comment',' Lit., 'doubt of a doubt'. Firstly there is the doubt whether the blood emanated from the woman or from the man; and secondly, even if it emanated from the woman, there remains the doubt previously mentioned (cf. prev. n.). ');">¹⁸</span>

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