Bava Kamma 106A

בפקדון ⁠– פסול לעדות.

but one who denies a claim concerning having taken a deposit is disqualified from bearing witness, because if it is clear that the deposit is in his possession, yet he denies it, he must be lying.

והאמר אילפא: שבועה קונה: שבועה היא דקניא, אבל כפירה לא קניא! הכא נמי ⁠– דקיימא באגם.

The Talmud raises a further difficulty with regard to Rav Sheshet’s opinion: But didn’t Ilfa say that an oath effects acquisition, meaning that once he testified falsely that he did not become a bailee, the item in question becomes his property, rendering him liable as a robber even for damage or loss resulting from accidents? The Talmud infers: It is the taking of an oath that effects acquisition, but mere denial of having become a bailee does not effect acquisition. The Talmud rejects this distinction: Here too, Ilfa must be referring to a case where the deposit stands in a place not in the bailee’s possession, e.g., a swamp, and as long as he does not take an oath, it can be assumed that his intention is simply to be evasive. But if the animal was standing in his house, then he acquires it as soon as he denies the claim.

ואיבעית אימא: מאי ״שבועה קונה״⁠ – כדרב הונא; דאמר רב הונא אמר רב: ״מנה לי בידך״, והלה אומר: ״אין לך בידי״; ונשבע, ואחר כך באו עדים ⁠– פטור, שנאמר: ״ולקח בעליו ולא ישלם״⁠ – כיון שקבלו הבעלים שבועה, שוב אין משלם ממון.

And if you wish, say instead: What is the meaning of Ilfa’s statement that an oath effects acquisition? It is in accordance with the statement of Rav Huna, as Rav Huna says that Rav said that if one party says: I have 100 dinars in your possession, and the other party says: You do not have any money in my possession, and the latter took an oath to that effect, and later, witnesses came and testified that his oath was false, he is exempt, as it is stated: “The oath of YHWH should be between them both, to see whether he has not put his hand to his neighbor’s goods; and the owner thereof should accept it, and he should not make restitution” (Exodus 22:10); teaching that once the owner received an oath, the one who took the oath no longer pays monetary restitution. Ilfa’s statement that an oath effects acquisition means that the bailee will no longer have to pay monetary restitution, and it does not relate to Rav Sheshet’s statement that the bailee becomes responsible for damage resulting from accidents as soon as he denies the claim.