Reference for Bava Batra 351:2
הוציא עליו כתב ידו שהוא חייב לו גובה מנכסים בני חורין וכו': בעא מיניה רבה בר נתן מר' יוחנן הוחזק כתב ידו בבית דין מאי אמר ליה אף על פי שהוחזק כתב ידו בבית דין אינו גובה אלא מנכסים בני חורין
It 'may be recovered from the heirs' in order that doors might not be locked in the face of borrowers;<span class="x" onmousemove="('comment',' No one would be able to obtain a loan if creditors could not be assured of recovering it from the debtor's heirs. ');"><sup>3</sup></span> 'but may not be recovered from the buyers', because it is not [sufficiently] known.<span class="x" onmousemove="('comment',' V. p. 775, n. 3. Unlike a loan secured by a bond, it is neither made, nor acknowledged in the presence of witnesses nor in the presence of a scribe. Hence no one besides the lender and debtor may ever be aware of its existence. The buyers of the debtor's property must, therefore, be protected against loss not due to any Fault of theirs. ');"><sup>4</sup></span>