Reference for Bava Metzia 101:12
ואי כתב רחמנא לוקח משום דקא קני דאמרי אינשי זבנית קנית אבל מוכר דאבודי קא מוביד דאמרי אינשי זבין אוביד אימא לא אזהריה רחמנא בלא תונו צריכא:
A man had jewellery for sale. He demanded sixty [<i>zuz</i>], whilst it was worth fifty; yet had he been offered fifty-five, he would have accepted. Then a man came and argued. 'If I give him fifty-five, it will constitute renunciation: therefore I will give him sixty and then sue him at law.' When he came before R. Hisda, he said to him: This was taught only of one who buys from a merchant; but when one buys from a Private individual, he has no claim of fraud against him. Said R. Dimi to him: 'Well spoken!'<span class="x" onmousemove="('comment',' Lit., (with [H], 'thy strength', understood) 'thy strength be firm'. ');"><sup>11</sup></span>