Deriving benefit from melachos performed on Shabbos

May one benefit from a melacha performed on Shabbos. For example, someone switched on a light in a room, may one read with that light. A sefer was carried through a carmelis or a reshus harabim, may one read that sefer on Shabbos?

To answer this question, we are required to familiarize ourselves with the sugya in the gemora.

There is a famous machlokes between R’ Me’ir, R’ Yehuda and R’ Yochanan Hasandlar regarding eating food that was cooked on Shabbos. The Bais Yosef, in the beginning of simon 318 mentions the places in Shas where one can find this machlokes.

	B’shogaig		B’maizid
	For the cook	For others	For the cook	For others
R’ Me’ir	Muter on Shabbos	Muter  on Shabbos	Muter after Shabbos	Muter after Shabbos
R’ Yehuda	Muter after Shabbos	Muter after Shabbos	Ossur forever	Muter after Shabbos
R’ Yochanan Hasandlar	Ossur forever	Muter after Shabbos	Ossur forever	Ossur forever

Notice that where the former opinion leaves off, the next opinion begins! I.e. the maizid of R’ Me’ir is the shogaig of R’ Yehuda.

Is the prohibition of biblical nature or rabbinic?

It is rabbinic, i.e. it is ossur mid’oraisso to cook on Shabbos but deriving benefit is only an issur d’rabanan.

Can you provide examples based on the above machlokes?

Someone walked into a room on Friday night and absentmindedly switched on the light. His action is deemed a shogeig – unintentional, because he momentarily forgot that it was Shabbos.

According to R’ Me’ir one may benefit from this light on Shabbos, as Chazal did not impose a penalty when the action was b’shogeig. According to R’ Yehuda one may not benefit from this light on Shabbos.

Is the halacha in accordance with R’ Me’ir or R’ Yehuda?

This too is a machlokes. The Beis Yosef writes that the Rif, Rambam, Ba’al Halachos Gedolos, She’iltos, Ramban and Rosh ruled in accordance with R’ Yehuda. The Mechaber [1] only cites the opinion of R’ Yehuda.

On the other hand Tosefos and Sefer haT’ruma rule in accordance with R’ Me’ir. The Vilna Ga’on paskens according to Tosefos.

The Mishna Berura [2] concludes that the halacha is like R’ Yehuda but if necessary one may rely on R’ Me’ir, when done b’shogeig

Consequently, one may not benefit from the light on Shabbos, even though it was switched on unintentionally, because halacha is with R’ Yehuda. If necessary, there is room to rely on R’ Me’ir and benefit from the light, but a Rav must be asked as to the definition of “necessary”. Sephardim must be more stringent because the Mechaber does not present another opinion other than R’ Yehuda.

Can we make this l’ma’ase?

Several examples intended to heighten our awareness but not intended as a p’sak:

v     Betty peeled eggs two hours prior to the meal and went to shul. She violated a biblical issur of borer and according to halacha she and others may not consume the eggs that Shabbos. [3] We assume it is b’shogeig because she has no intention to want only violate the Shabbos, rather it is her ignorance that perpetuates this violation. A Rav should be asked.

v     Moish unknowingly carried tissues in his pocket home from shul in a place without an eiruv. Upon arriving home he realizes that he carried tissues in a prohibited manner and enquires as to the status of the tissues. Halacha is that he may not blow his nose with the tissues, because they were carried home through a Shabbos violation.

One might ask that the tissues are not modified as a consequence of the violation, unlike cooking where the item is modified, so perhaps one may use the tissues? The Chayei Adam [4] used this distinction to differentiate between melachos but concludes that one must be stringent with respect to an issur d’oraisso, which means that Moish may not blow his nose with those tissues. A Rav should be asked.

v     Yenta removed cold chicken with gravy and placed it directly onto a hotplate on Shabbos. Halacha is that the gravy may not be reheated on account of bishul [5] and if so done, may not be eaten. [6]