Reference for Yevamot 5:10

כיון דבמקום מצוה הוא דאסירה צרה ושלא במקום מצוה שריא משום הכי תני פוטרות

[that <i>halizah</i> also need not be performed]. Let it then be stated,<span class="x" onmousemove="('comment',' In our Mishnah. ');">²⁵</span> 'She is forbidden to perform <i>halizah</i>!<span class="x" onmousemove="('comment',' And, consequently, the expression 'prohibit' which is preferable to that of 'exempt' (v. supra notes 6 and 8) could well be used for the levirate marriage. ');">²⁶</span> — No harm, surely, is thereby done.<span class="x" onmousemove="('comment',' Lit., 'what does he do', i.e., there is no reason why halizah should be forbidden. Hence the expression of 'prohibit' could not properly be used. ');">²⁷</span>

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