Commentary for Kiddushin 44:9
תנא אף בחליפין ותנא דידן מילתא דליתא במטלטלין קתני מילתא דאיתא במטלטלין לא קתני
THE SAGES MAINTAIN: BY MONEY, THROUGH HIS OWN AGENCY, AND BY DEED, THROUGH THE AGENCY OF OTHERS;<span class="x" onmousemove="('comment',' Who receive the deed for him.');"><sup>15</sup></span> PROVIDING THAT THE MONEY IS FURNISHED BY OTHERS.<span class="x" onmousemove="('comment',' The money is given to him specifically for that purpose, and he gives it to his master. But if the slave finds money, or has it given him, it belongs to his master.');"><sup>16</sup></span> <big><b>GEMARA: </b></big>How do we know this? - Because it is written: And ye shall make them [the heathen slaves] an inheritance for your children after you, to possess as an inheritance;<span class="x" onmousemove="('comment',' Lev. XXV, 46.');"><sup>17</sup></span>
Daf Shevui to Kiddushin
The tanna of our mishnah does not disagree with this law. He just does not include it because halifin can also be used to acquire movable property. The mishnah lists ways of acquisition that cannot be used to acquire movables.