Commentary for Bava Batra 55:7

אי מה שור המועד עד נגיחה רביעית לא מיחייב ה"נ עד שנה רביעית לא קיימא ברשותיה הכי השתא התם מכי נגח שלש נגיחות הוי מועד

a field for three years it passes [entirely] out of the possession of the seller and is established in the possession of the buyer.<span class="x" onmousemove="('comment',' I.e., so completely that he need no longer retain his title-deeds. ');">¹⁹</span> It may be objected to this that just as in the case of the goring ox its master does not become liable<span class="x" onmousemove="('comment',' To pay the full damage. ');">²⁰</span> till the fourth goring, so here the property should not become the fixed possession of the holder<span class="x" onmousemove="('comment',' If be can bring no proof of ownership. ');">²¹</span> till the end of the fourth year? — How can you compare the two cases.<span class="x" onmousemove="('comment',' Lit., 'so now' ');">²²</span> There, as soon as the ox has gored three times, it is regarded as <i>Mu'ad</i>,

Rashi on Bava Batra