Word To The Wise

The Gemara in Shabbos explains that various halachos are learned from a pasuk in Yeshayah (58:13). From the words “Mimtzo cheftzecha,” we derive that one should not occupy himself on Shabbos with conducting his business affairs. This includes pursuits that would have otherwise been permitted. For example, one should not examine his house that is under construction to see how the work is progressing. All he is doing is taking a stroll through his house and seemingly not violating Shabbos, yet the verse of “Mimtzo cheftzecha” precludes even that activity.
From the words “V’dabeir davar,” the Gemara derives that one’s speech on Shabbos should not be the same as his speech during the week. Rashi explains that one should not discuss his business affairs on Shabbos. Rabbeinu Tam questions that explanation, since discussing one’s business affairs should have already been precluded from the words of “Mimtzo cheftzecha.” Tosefos offer an entirely different explanation. One should speak less on Shabbos than he does during the week. This does not include any mitzvah-related speech, but rather mundane topics like politics and sports. The Bach defends Rashi and explains that there is a difference between business-related actions such as taking a walk through a factory and business-related speech. Both are forbidden but the source is from two different verses.