Source and decoding
דאמר רבי יוחנן: שבועה זו תקנת חכמים היא, שלא יהא כל אחד ואחד הולך ותוקף בטליתו של חבירו ואומר: שלי הוא.
Rabbi Yohanan said: This oath is a rabbinic enactment, so that a person will not seize another’s garment and say, “It is mine.”
Rabbi Yohanan explains the oath as a rabbinic safeguard against opportunistic grabbing. Division alone could reward seizure. This does not prove either claimant stole: simultaneous lifting is possible. Separate risk from fact and division from the oath’s purpose.