Yerushalmi Bava Metzia 1:3 ירושלמי בבא מציעא א׳:ג׳

MISHNAH: Somebody was riding on an animal when he saw a find and said to another person: “give it to me”. If [that one] took it and said: “I acquired it”, he acquired it³²Since ownerless property only can be acquired by action, never by intent or declaration (cf. Ketubot 5:5, Note 100.. If after he had handed it over, he said: “I acquired it first,” he did not say anything³³The rider acquired the object by grabbing it in his hand; he is the presumed owner. The walker is now a claimant and “the burden of proof is on the claimant”. If he did not articulate his claim before handing over the object there can be no witnesses and no proof..

HALAKHAH: “Somebody was riding on an animal,” etc. Rebbi Isaac says, from this rule one cannot infer anything, not from its beginning nor from its end. “Somebody was riding on an animal when he saw a find and said to another person: ‘give it to me’. If [that one] took it and said: ‘I acquired it’, he acquired it”. If he had said, “acquire it for me”, he would have acquired it. That means, from this rule one cannot infer anything, not from its beginning nor from its end³⁴As Pene Moshe points out, this refers to the disagreement between R. Joḥanan and R. Simeon ben Laqish (Peah 4:6, Note 112), on whether a person can acquire a find for another person by lifting it. The Mishnah does not help in solving the dispute. The first sentence does not help since it does not exclude that had the rider said, “acquire it for me” instead of “give it to me”, the walker would have acquired it for the rider by lifting and would not have been able to claim that he acquired it. The second sentence does not have to be quoted since it obviously is irrelevant for the disagreement between R. Joḥanan and R. Simeon ben Laqish..