Related for Eruvin 74:6
הא ודאי איפכא תניא דקתני סיפא ומודה רבי יוסי באומר מעשר שיש לי בתוך ביתי יהא מחולל על סלע חדשה שתעלה בידי מן הכיס שחילל מדקאמר הכא שחילל מכלל דהתם לא חילל
Now since he<span class="x" onmousemove="('comment',' R. Jose.');"><sup>16</sup></span> ruled here that it 'is redeemed' it follows that in the previous<span class="x" onmousemove="('comment',' Lit., 'there'.');"><sup>17</sup></span> case [his ruling was that] it is not redeemed.<span class="x" onmousemove="('comment',' The ruling in the first clause must consequently be changed from the positive to the negative.');"><sup>18</sup></span> What, however, is to be understood [by the case of] the new sela'?
Tosefta Demai
[If] an am ha'aretz who said to a chaver, "Buy me a bunch of vegetables," [or] "[Buy me] a loaf of bread," Rabbi Yosei says, there is no need [for the chaver] to tithe [what he purchased for the am ha'aretz, see Dem. 6:12]. Rabbi Yehudah says, he needs to tithe. Rabbi Shimon ben Gamaliel says, if he exchanges the money (i.e., he uses his own money rather than the am ha'aretz's money to purchase the vegetables or the bread, see Minchat Yitzchak here), he needs to tithe.
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