TT #644 · 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 Sifrei Devarim / Yevamot.
TT lemma: כִּי יֵשְׁבוּ אַחִים.
נֶאֱמַר כָּאן כִּי יֵשְׁבוּ אַחִים וְנֶאֱמַר לְהַלָּן וְיָרַשְׁתֶּם וְיִשַׁבְתֶּם בָּהּ – מַה יְשִׁיבָה שֶׁלְּהַלָּן יְשִׁיבָה שֶׁיֵּשׁ עִמָּהּ יְרוּשָׁה, אַף יְשִׁיבָה שֶׁבְּכָאן יְשִׁיבָה שֶׁיֵּשׁ עִמָּהּ יְרוּשָׁה.
English: It is said here “When brothers dwell” and it is said elsewhere “and you shall inherit it and dwell in it” — just as the dwelling there is a dwelling that involves inheritance, so the dwelling here is a dwelling that involves inheritance.
On the daf / in context: Gezerah shavah links the two occurrences of “dwelling” to restrict the law to brothers who inherit from one another (paternal brothers).
Gezerah shavah on “yeshivah.”
The brothers subject to yibbum are those who share inheritance rights — paternal brothers only.