Reference for Kiddushin 55:10
<big><strong>גמ׳</strong></big> חליפין מאי ניהו מטבע שמע מינה מטבע נעשה חליפין אמר רב יהודה הכי קאמר כל הנישום דמים באחר
- I might have thought, Only land is it usual for people to sell secretly: had he sold it, it would not be generally known; but as for this,<span class="x" onmousemove="('comment',' The claim under discussion.');"><sup>14</sup></span> had he sold himself, it would have been known.<span class="x" onmousemove="('comment',' Lit., 'It has a sound.' Hence the claim is prima facie false, and no superimposed oath is taken, for this too requires some verisimilitude');"><sup>15</sup></span> Therefore we are informed [that it is not so]. <big><b>MISHNAH: </b></big>WHATEVER CAN BE USED AS PAYMENT FOR ANOTHER OBJECT, AS SOON AS ONE PARTY TAKES POSSESSION THEREOF, THE OTHER ASSUMES LIABILITY FOR WHAT IS GIVEN IN EXCHANGE.<span class="x" onmousemove="('comment',' I.e., for the halipin, or barter thereof.');"><sup>16</sup></span> HOW SO? IF ONE BARTERS AN OX FOR A COW, OR AN ASS FOR AN OX, AS SOON AS ONE PARTY TAKES POSSESSION, THE OTHER BECOMES LIABLE FOR WHAT IS GIVEN IN EXCHANGE.<span class="x" onmousemove="('comment',' Even before it actually reaches his hands.');"><sup>17</sup></span> <big><b>GEMARA: </b></big>What is the barter? Money!<span class="x" onmousemove="('comment',' For it is assumed that WHATEVER CAN BE USED AS PAYMENT refers to, or at least includes, money. Hence the Mishnah teaches: If A exchanges a cow for B's money, the money not being given as payment but as barter, just as an ox might have been given, immediately A receives the money, B accepts the risks of anything that may happen to the cow, which is now in his possession. That is so, notwithstanding that had the money been given as payment, A's receipt thereof would not have transferred ownership of the cow to B.');"><sup>18</sup></span> Then this proves that coin can become [an object of] barter.<span class="x" onmousemove="('comment',' This is disputed by Amoraim in B.M. 46a, hence the Mishnah refutes the opposing view.');"><sup>19</sup></span> - Said Rab Judah: This is its meaning: Whatever is assessed as the value of another object,<span class="x" onmousemove="('comment',' I.e., anything but money, which needs no assessment.');"><sup>20</sup></span>