Reference for Bava Metzia 156:10

אם כן ליתני מפני החשד מאי מפני שמעביר על דעתו של בעל הבית שמע מינה משום דשני הוא וכל המעביר על דעת של בעל הבית נקרא גזלן

and the poor may not buy [even] shoestraps therewith, unless it was stipulated in the presence of the members of the community [that such shall be permitted]: this is the ruling of R. Jacob, stated on R. Meir's authority; but R. Simeon b. Gamaliel is lenient [in the matter].<span class="x" onmousemove="('comment',' It is assumed that the reason of R. Meir's stringency is that the poor, by disregarding the donor's wish, become robbers, and therefore all such diversions are forbidden. ');">¹⁰</span>

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