Reference for Bava Metzia 19:17

הכא במאי עסקינן דלא אמר אקני

— but not servants to servants.<span class="x" onmousemove="('comment',' The freedom of the individual ought not to be jeopardised by an engagement which is to bind the employee to work for the employer against his own inclination, as if he were the employer's chattel, Cf. B.K. 116b. ');">¹⁷</span>

Jastrow