Nedarim 89
איבעית אימא הא דאפקריה באנפי תרין והא דאפקריה באפי תלתא דאמר ר' יוחנן משום רבי שמעון בן יהוצדק כל המפקיר בפני שלשה הוי הפקר בפני שנים לא הוי הפקר
Alternatively: One case refers to hefker declared in the presence of two; the other, if declared before three. For R. Johanan said in the name of R. Simeon b. Jehozadak: Hefker declared in the presence of three is valid, but not in the presence of two.<span class="x" onmousemove="('comment',' Until one actually takes possession. Therefore, in the Mishnah, since no person is present, R. Jose maintains that if the maddir declares the food hefker, and the muddar takes it, he receives it directly from the maddir. But the vineyard, we assume, was renounced in the presence of three; therefore even R. Jose agrees that the renunciation is immediately valid. Hence, if he re-acquires it, it is exempt from tithe. The stronger validity of hefker in the presence of three is due to its greater publicity. ');"><sup>1</sup></span>
ור' יהושע בן לוי אמר דבר תורה אפילו באחד הוי הפקר ומה טעם אמרו בשלשה כדי שיהא אחד זוכה ושנים מעידין:
R. Joshua b. Levi said: By the Torah, it is hefker even if declared in the presence of one: why then are three required? So that one can take possession, and the other two attest it.<span class="x" onmousemove="('comment',' For otherwise the first owner can deny his renunciation. ');"><sup>2</sup></span>