TT #667 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:05
When brothers dwell together and one of them dies and has no son, the wife of the dead shall not be outside to a strange man; her husband’s brother shall come upon her and take her to himself as a wife and perform the duty of a husband’s brother for her.
Torah Temimah points to Yevamot 8b / 11a.
TT lemma: וְיִבְּמָהּ.
עָלֶיהָ – וְלֹא עַל צָרָתָהּ.
English: “Upon her” — and not upon her co-wife.
On the daf / in context: The singular “upon her” excludes the co-wife from being taken in yibbum when the primary yevamah is an ervah.
Mi’ut from the singular pronoun.
When the yevamah is an ervah to the yavam, her co-wife is also exempt from yibbum and chalitzah.