Chapter 29
Laws Derived from Isaiah: Running, Walking, Commerce, Measuring, Reading, Speaking
SPEAKING ABOUT THINGS ONE IS FORBIDDEN TO DO ON SHABBATH AND YOM TOV
60.a. It is proper, when one can, to take a strict approach speaking and not to talk on Shabbath about a forbidden act one about intends to do after Shabbath, even if the act is to be done in the performance of a mitzva
60.b. An exception occurs where there is a particular need to speak about the act on Shabbath, for example
1) when one wishes to ask a friend one happens to see on Shabbath to accompany one in one’s car after Shabbath for the purposes of a mitzva, or
2) when one is afraid of being remiss in the performance of the mitzva after Shabbath and wishes to stimulate one’s enthusiasm by talking about it.
61.a. It is forbidden to make calculations (aloud) on Shabbath if there is a possibility that the calculations may be of some use to one.
61.b. There is no prohibition against making a calculation (not in writing, of course) which can be of no practical use.
61.c. As explained in paragraph 55 above, one may also make verbal calculations for the purposes of a mitzva.
