Reference for Yevamot 217:5

רבא אמר לעולם פשיטא לרבי אלעזר דמיתה מפלת ומיהו הכל בקיאין בגירושין ואין הכל בקיאין בחזרה

He was in doubt whether it was death<span class="x" onmousemove="('comment',' Of the childless husband, ');">¹⁴</span> that subjects [the widow to the levirate marriage] or whether it was the marriage that preceded it<span class="x" onmousemove="('comment',' Lit.,'the first'. ');">¹⁵</span> that subjects her to it. If it is death that subjects her to it, she should be subject to the<span class="x" onmousemove="('comment',' Lit., 'behold she is thrust before him'. ');">¹⁶</span> levirate marriage; and if it is the marriage preceding it<span class="x" onmousemove="('comment',' Lit.,'the first'. ');">¹⁵</span>

Jastrow

Jastrow

Jastrow

Jastrow