Reference for Yevamot 64:1
אמר ר' אבהו מודה ר' יוסי באיסור מוסיף
— R. Abbahu replied: R. Jose admits<span class="x" onmousemove="('comment',' That one prohibition may be imposed upon another. ');"><sup>1</sup></span> where the latter prohibition is of a wider range.<span class="x" onmousemove="('comment',' [H] lit., 'a prohibition which adds', i.e., one which causes an object (or a person) to be forbidden to others to whom it was not previously forbidden. Hence he admits the imposition of the prohibition of 'brother's wife' upon that of 'wife's sister', even where the latter prohibition was already in force, because the former, unlike the latter, is applicable not only to him alone but to the other brothers also. In the case, however, of a married woman who became his mother-in-law where the first prohibition was of a wider range (the woman being forbidden to all men except her husband) and the later one (forbidden to him only) of a restricted range, the second prohibition cannot be imposed upon the first. The reason why in the case of a mother-in-law who became a — married woman the sentence is to be that for an offence against a mother-in-law is not because the latter (which is of a wider range) cannot be imposed upon the former, but because wherever two penalties are to be inflicted the severer one (burning) supersedes the lighter one (strangulation). ');"><sup>2</sup></span> This is satisfactory in the case where the surviving brother had married<span class="x" onmousemove="('comment',' One of the sisters. ');"><sup>3</sup></span>