TT #649 · 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 17b.
TT lemma: וּמֵת אַחַד מֵהֶם.
וּמֵת אַחַד מֵהֶם – מִשְׁמַע מִיתָה וּמִשְׁמַע שֶׁיֵּשׁ לוֹ אַחִים.
English: “And one of them dies” — the language implies both death and that there are surviving brothers.
On the daf / in context: The verse presupposes that brothers remain after the death, establishing the basic condition for the zikah.
Derash on the plain implication of the verse.
Yibbum applies only when at least one brother survives the deceased.