Reference for Yevamot 243:4

ושוב מעשה בקולר של בני אדם שהיו מהלכין לאנטוכיא ובא עובד כוכבים אחד ואמר חבל על קולר של בני אדם שמתו וקברתים והשיאו את נשותיהם ושוב מעשה בששים בני אדם שהיו מהלכין לכרכום ביתר ובא עובד כוכבים ואמר חבל על ששים בני אדם שהיו מהלכין בדרך ביתר שמתו וקברתים והשיאו את נשותיהם:

of men, for they died and I buried them', and [on this evidence] their wives were permitted to marry again. Moreover, it happened that sixty men were going to the camp<span class="x" onmousemove="('comment',' [H], a battleground, cf. castra. ');">¹⁵</span> of Bether,<span class="x" onmousemove="('comment',' The town where in 135 C.E. Bar Kokeba fought his last battle against the Romans. ');">¹⁶</span> and an idolater came and stated, 'Alas for sixty men who were on the way to Bether, for they died and I buried them', and [on the basis of this statement] their wives were permitted to marry again. <b><i>MISHNAH</i></b>. EVIDENCE<span class="x" onmousemove="('comment',' That a man is dead. ');">¹⁷</span> MAY BE TENDERED [EVEN IF THE CORPSE WAS SEEN BY THE WITNESSES] IN CANDLE LIGHT OR IN MOONLIGHT; AND A WOMAN MAY BE GIVEN PERMISSION TO MARRY AGAIN ON THE EVIDENCE OF A MERE VOICE.<span class="x" onmousemove="('comment',' [H] li. 'daughter of the voice', 'echo', even if the person who uttered it was not seen, as in the case given infra. ');">¹⁸</span>

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