In this week’s parshah, Parshas Va’eschanan, we find the second set of the Asseres Hadibros. The fourth command in both sets is to keep Shabbos, but there are variations between the two. In Parshas Yisro, where the first set appears, the Torah writes “zachor es yom haShabbos l’kadesho. ” In this week’s parshah the Torah writes “shamor es yom haShabbos l’kadesho.”
The Gemara in Shavuos 20b says that Hashem actually said both of these pesukim at the same time. The Gemara says that this is a phenomenon, which a human cannot say – or even hear. The Gemara also derives from this that women are obligated in the mitzvah of Kiddush on Shabbos despite the fact that it is a mitzvas assei she’hazeman gramma. The mitzvah of Kiddush is derived from the pasuk of zachor, and the pasuk of shamor is the source for the lo sa’aseh of Shabbos. The Gemara says the fact that they were said at once teaches us that they are connected and therefore, anyone who is obligated in the lo sa’aseh of Shabbos – which includes women – is also obligated in the assei of Shabbos, namely to recite Kiddush.
The Ramban, in Parshas Yisro (20:8), asks: if Hashem said both of these pesukim, why were both not written in the luchos? He answers that perhaps both were written in the first set of luchos and that in the second set only zachor was written. And, the Ramban says, maybe Moshe explained that the mitzvah of shamor goes along with it.
The Rambam, in Hilchos Shabbos 30:1, says that there are four things said about Shabbos: two are from the Torah and two are midivrei sofrim that were explained by the nevi’im. The two from the Torah are zachor and shamor. The two that are midivrei sofrim are kavod and oneg Shabbos.
It is apparent from the Rambam that oneg and kavod Shabbos are not separate mitzvos; rather, they are connected to zachor and shamor. In other words, the mitzvah of zachor is not only to recite Kiddush over a cup of wine; it also includes all actions that honor and respect the sanctity of Shabbos. Through such actions one not only honors and respects Shabbos, but is also mekadeish the day as a day of honor. When one fulfills oneg Shabbos he also fulfills the mitzvah of zachor.
The Rambam says that in order to honor Shabbos, one must wash his hands, face, and feet with warm water on Friday. One must also wear clean clothing that differs from his weekday attire. Additionally, one should not conduct a seudah on Friday afternoon so that he enters Shabbos with an appetite. One must set his table in a different way from the way it was set before Shabbos, and he must clean his house for Shabbos. Lighting candles is also an obligation in order to be kavod Shabbos. And oneg Shabbos includes eating well on Shabbos.
We see from another halacha in the Rambam (Hilchos Shabbos 30:8) that the mitzvah of honoring Shabbos is not a separate mitzvah, but rather it is connected to the mitzvah of being mekadeish by separating Shabbos from the chol. The Rambam says that a very wealthy person who eats elegantly every day of the week must change something in his menu in order to make Shabbos special. If he cannot change his menu, he should eat at a different time.
It is evident from this halacha that the obligation to honor Shabbos requires one to act differently on Shabbos than the way he acts on all other days. As stated above, these requirements were explained by the nevi’im – but are a fulfillment of the Torah mitzvah of zachor.