Reference for Sanhedrin 114:18

אמר רב נחמן בר יצחק מאי אשת איש דקתני כגון שנכנסה לחופה ולא נבעלה דלדידהו לית להו דיינינן להו בדינא דידן

— The latter text refers to adultery with a woman of their own [i.e., with a heathen married woman]; the former to adultery with one of ours [i.e., a Jewish married woman], for the second clause teaches: If he committed incest with a Jewess, he is judged according to Jewish law. With regard to what is this?<span class="x" onmousemove="('comment',' Since by the Noachian Law also he is liable to death. ');">¹⁵</span>

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