TB Bekhorot 18 The difference between teffilin and lulav when comes to borrowing the

Daf TB Bekhorot 18b discusses who is obligated of the giving the bekhor, the firstborn of a sheep or cattle, to the kohen when somebody gives another person a sheep to guard. That sheep is kept together with the homeowner’s sheep. Only one of the sheep is a firstborn. One of the sheep dies, but nobody knows which one was the firstborn. Rabbi Akiva holds the onus of proof that the living sheep is the firstborn lies upon the  kohen. “Rabbi Tarfon holds: The homeowner transfers to the priest a portion of his courtyard so that the priest should acquire the firstborn offspring located there, because it is suitable for him that the mitzva of giving the firstborn to a priest should be performed.” (sefaria.org translation)

The desire to observe a mitzvah is underlying principle Rabbi Tarfon’s approach. The owner of the courtyard wants to observe the law of the firstborn; consequently, he transfers a portion of his courtyard to be kohen so that the firstborn automatically goes to the kohen.

Rabbi Tarfon’s approach has a practical halakhic ramification. A person goes to shul and doesn’t have a pair of tefillin. He sees the teffilin laying on the bench. May he use them without asking permission? The Shulkhan Arukh Orakh Hayim, Siman 25, Seif 12 rules yes. The presumption is the owner of the tefillin is happy and please when a mitzvah is performed using his property.

Nevertheless, there are key conditions and limits.

·        Location: You may only use the tefillin in the exact area or room where the owner left them. You cannot take them home or to a different building.

·        Occasional Use Only: It must be an occasional or one-time use; you cannot borrow them regularly or systematically without asking.

·        No Objections: If you know or suspect the owner is particular (or if there is a note/sign forbidding use), you may not use them.

·        Cleanliness and Condition: The borrower must be clean and unkempt/sweat-free. If the owner is present, you should always ask rather than assume permission.

·        Restoration: If the straps or tefillin were folded when you found them, you must refold/tidy them back up after use.

Unlike teffilin this presumption that the owner of the  lulav and etrog is happy that a person is using his lulav and etrog without permission is not applicable. We learn that the lulav and etrog must be owned by the person and not borrowed or stolen on the first day of Sukkot. The Torah states, "And you shall take for yourselves on the first day..." (Leviticus 23:40).

The Hebrew word lakhem (לָכֶ֜ם/ "for yourselves") is interpreted by the Sages to mean that the four species must strictly belong to you, rather than being borrowed or stolen. This ownership requirement applies explicitly to the first day of Sukkot (or the first two days outside of Israel, where Yom Tov is observed for two days). From the second (or third) day onward, one may borrow someone else's set.

If someone wants to let another person use their lulav and etrog on the first day, they typically transfer legal ownership as a temporary conditional gift (matanah al t'nat le-hakhyil), after which the recipient can return it.