Reference for Bava Metzia 235:16
אלא אמר רב נחמן לא קשיא כאן בהגבהה כאן בהבטה
Raba said to R. Nahman: [When he is employed] on his own, what is the reason [that he is not heeded]? Because he [the labourer] can say to him, 'You are responsible for my wages'? [But when employed] by his neighbour he can also say to him, 'You are responsible for my hire'! For it has been taught: If one engaged an artisan to labour on his [work], but directed him to his neighbour's, he must pay him in full, and receive from the owner [of the work actually done] the value of the labour whereby he benefited! — But, said R. Nahman, there is no difficulty: here it refers to his own; there, to that of <i>hefker</i>.<span class="x" onmousemove="('comment',' V. Glos. R. Nahman maintains (supra 10a) that if a person lifts up an object of hefker on his neighbour's behalf, it belongs to himself. Hence, when a worker collects sheaves of hefker for an employer, they belong to himself, and therefore the offer must be accepted. ');"><sup>12</sup></span>