Some actions are prohibited because they spoil the atmosphere of sanctity and relaxation of Shabbat, while others are prohibited because they are considered preparation on Shabbat for a weekday.

Any kind of commerce is prohibited on Shabbat. It is prohibited even to read financial reports or documents or anything related to business.

One may not take measurements of a space or object on Shabbat. Likewise, it is prohibited to weigh people or objects on Shabbat, even with a non-electronic scale.

One should not give gifts on Shabbat, apart from food and drink or items that are to be used on that Shabbat, provided that it is actually permitted to use them on Shabbat.

The sanctity of Shabbat should also be evident in one’s manner of walking. On Shabbat one should walk with restraint; he should not run or even walk fast. If one wants to run because of the rain or for the purpose of a mitzva, e.g., to get to the synagogue in time for prayers, it is permitted. Running in order to provide urgent medical assistance or to save someone from danger is obviously permitted.

Further reading: For more on the sanctity of Shabbat, see A Concise Guide to the Sages, p. 275; A Concise Guide to Mahshava, p. 33.

One may not prepare on Shabbat for a weekday or even for a future Shabbat. This prohibition applies even in the case of preparing for a mitzva, such as washing dishes in order to serve the melaveh malka meal after the conclusion of Shabbat.

It is prohibited to walk on Shabbat to one’s workplace in order to start work immediately after Shabbat. It is also prohibited to go to see an apartment with the thought of buying or renting it after Shabbat. By the same token, it is prohibited to tour a marketplace or a fair to examine goods that one is thinking of purchasing.

The above prohibition applies only if the action itself clearly discloses one’s intention. For example, if a contractor visits a construction site and examines the progress of the work, the purpose of the tour is obvious to all, and therefore it is prohibited. But if one is strolling along and happens to approach a certain place where he must do some work after Shabbat, he has not violated the prohibition of “seeking your needs,” as an onlooker would assume that he is simply enjoying a walk.

Notwithstanding the above, it is permitted to stop in the street in front of a shop window to view the display, if one does not intend to buy the items displayed. In this context it is important to emphasize that the permission applies only to looking at the display itself; one may not examine the price labels.

It is permitted to learn Torah on Shabbat in order to prepare for a lesson or test later in the week. Some permit students to study even for tests in secular subjects on Shabbat, such as science. The reason for this lenient ruling is that the learning itself provides immediate benefit by enriching the student.