Halakhah for Yevamot 34:9
והא מהיכא תיתי יבום בנחלה תלא רחמנא ונחלה מן האב ולא מן האם היא איצטריך סד"א הואיל וחידוש הוא דקמשתרי ערוה גביה אימא עד דמייחדי באבא ובאמא צריכא
is not available for deduction,<span class="x" onmousemove="('comment',' Lit., 'vacant'. ');"><sup>21</sup></span> your statement would be negatived,<span class="x" onmousemove="('comment',' [H] (cf. Jast.) or [H] (cf. Levy). Contract. of [H] 'not it'. Aruk: derivation is from [H] + [G] 'not so my son'. ');"><sup>26</sup></span> [the analogous word] being indeed available; for whereas he could have written 'friends' and yet wrote 'brethren', the inference must be that the object was to render it available for analogous deduction; hence the All Merciful has written 'together', implying only those who are together in respect of inheritance.<span class="x" onmousemove="('comment',' V. supra p. 95, n. 7. ');"><sup>27</sup></span> If, [on the other hand,] the All Merciful had only written 'together', it might have been said to refer to such as have the same father and mother; [hence both expressions were] required.