On the Commadment זכור את יום השבת לקדשו (Remember the Sabbath in order to sanctify it) Rashi teaches that the way to do this is by keeping shabbat in one’s memory. How does one do this? One should set aside something for shabbat during the week.

Interesting that Rashi doesn’t quote the Talmudic passage that required us to make Kiddush on wine זכרהו על היין (Remember it (shabbat) with wine). Instead, he gives us the custom of Shammai the elder as quoted in the Gemara Beitza where he differs with Hillel.

If Shammai found a plump calf on one day, he would set it aside for Shabbat, while Hillel would use it on that day, quoting the verse ברוך השם יום יום (Praise be God everyday).

Shammai, however, did not create this custom in order to remember shabbat, but to honor shabbat. Why does Rashi seem to conflate honor with memory?

Rashi likes Shammai’s custom because it achieves both qualities simultaneously. Shabbat is honored materially by setting aside the animal, but in so doing, it fulfills the requirement of memory, removing it from being a passive activity to being an active one. He actively recalls the shabbat as he sets aside the calf. By saying this calf will be saved for shabbat, he is remembering that it is special and he honors it by preparing ahead of time. If he finds a nicer calf the following day, he will set that aside and eat the previous calf. Each day affords an opportunity where shabbat may be remembered, but it is guaranteed that this active memory will be invoked at least once.

Rashi understands that “Remembering shabbat” needs to happen outside of Shabbat and therefore it is part and parcel of honoring shabbat. It is the ideal way to invest every day with the purpose of preparing and remembering shabbat.