Reference for Yevamot 211:11

אמר ליה אבוך היכא א"ל במתא אימך היכא א"ל במתא יהיב בהו עיניה ושכיבן:

— 'In town', the other again replied. He set his eyes upon them and they died. Our Rabbis taught:<span class="x" onmousemove="('comment',' Others read, 'Raba said' (She'iltoth section Ki Theze). ');">²⁷</span> A <i>halizah</i> under a false assumption is valid; a letter of divorce [given] under a false assumption is invalid.<span class="x" onmousemove="('comment',' If the condition on which it was given was not fulfilled. A condition in the case of divorce has legal validity, since a divorce may be effected through the agency of witnesses. V. Keth. 74a and cf. supra p. 730, n. 10, final clause. ');">²⁸</span>

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