Shabbos and cellphones

Are there issurei de'oraysas in using a cellphone on shabbos?

Shalom!

Thank you for your question.

There is a tremendous body of literature discussing the use of electricity on Shabbat and whether doing so would be an issur d’oraisa (a biblical prohibition) or an issur derabanan (a rabbinical prohibition). There is further discussion on the relationship between battery power and electric power. Ultimately, however, both battery and electricity use is forbidden, though most sources would rule that the use of a cellphone is a rabbinic violation. Here are some of the concerns:

Some sources compare the use of electricity with “mavier” lighting a fire. Lighting a fire on Shabbat is clearly a biblical violation. Other sources say its use is a violation of “boneh” – building, which in this context refers to completing (“building”) a circuit. There are also views that it is a violation of “makeh b’patish” – completing a circuit, and “bishul” cooking, in the event that metal components get red hot.

As mentioned, most sources would rule that the use of a cellphone is a violation of one or more of the above violations, though on a rabbinical level. This issue is purely academic as it is forbidden either way. The use of a cellphone also often involves texting/writing which is a rabbinical violation in its own right.

To conclude, the use of a cellphone is completely forbidden (unless of course needed for saving a life and other urgent security related issues). I will also add that a cellphone, like anything else that cannot be used on Shabbat is classified as “muktza” and may not be moved on Shabbat.