According to Rabbi Moshe Isserles, in the note that he adds to the end of paragraph 3 of Section 262, one of the very last things one should do on Friday afternoon before the onset of Shabbat is to wash and dress. The modern equivalent of this 'bathing' is, of course, taking a shower or a bath. In pre-modern times most people did not have their own bathroom and had to go to the local bath-house to perform their ablutions. In all probability this is the origin of the kabbalistic custom which has men going to bathe in the mikveh before Shabbat on Friday afternoons. (I would imagine that among Conservative Jews this custom is virtually unknown, though it is certainly in vogue among the ultra-orthodox and neo-orthodox in Israel today.) For those of us who are less mystically inclined, however, the mitzvah is performed by taking a shower or having a bath so that we shall be physically clean in order to receive Shabbat.
And this bathing before Shabbat is a kind of mitzvah! It is derived from the words of the prophet [Isaiah 58:13-14] which we have quoted on a previous occasion:
Therefore, as the time for Shabbat fast approaches, when everything around the household is ready for Shabbat, we should go and take a shower or bath and then get dressed in our Shabbat best. In many communities throughout the world pious Jews (of both sexes) have one special set of clothes that they wear only on Shabbat and YomTov. The Gemara [Shabbat 113a] teaches that "Your Shabbat clothes should not be the same as your weekday clothes". In a most insightful comment, Rabbi Avraham Danzig [1748-1820], in his work Ĥokhmat Adam points out that the best clothes that we wear on Shabbat are not for the benefit of those around us, they are in honour of Shabbat; therefore we should dress this way even when we are completely alone for Shabbat. We, certainly, should dress ourselves in a smart outfit - the kind we would wear if we were going to be presented to an important personality or on an important occasion when we want to look our best.
Rabbi Karo, in paragraph 2 of Section 262, recognizes however, that not everyone may be able to afford a special suit of clothes for Shabbat. He says that those who do not have such special clothing "should let their clothes hang down in best style". In earlier times people would wear a long outer garment that covered their body from the shoulders to the feet. During the week the men, at least, would hitch this garment up with a belt at their waist so that the bottom hem would not drag along the ground, gathering dirt and wearing away. But letting the garment fall so that the bottom hem reached the ground was a sign that one was not working, that one was relaxing. In modern times, even those who for whatever reason are not able to dress in their 'Shabbat best' for the arrival of the holy day, should check their clothing before Shabbat to make sure that they have not inadvertently left in their pockets things that are muktzeh, such as a pen in their top pocket or coins in another pocket. (The term muktzeh means 'set aside', and refers to objects that should be out of reach - and certainly out of use - during Shabbat, since their use does not suit the sanctity of Shabbat. There are several sub-categories of muktzeh, but I shall refrain from going into details unless asked to do so.)
This 'getting dressed to meet Shabbat' is not a charade. On second thoughts maybe it really is a special, holy, charade; for part of the 'magic' of Shabbat is achieved by the personification of Shabbat. The Gemara [Shabbat 119a] records two sages who really acted out this personification:
Most people know that this small note in the Gemara about how two sages would specially dress in order to 'greet' Shabbat was the seed from which the synagogue service which we now call Kabbalat Shabbat ['Reception of Shabbat'] grew into the beautiful and fragrant blossom that it is. One of the great tragedies that has beset the Jewish people throughout the ages was the expulsion of the Jews from Spain (2nd August 1492). Many of the Jews who were forced out of Spain went to North Africa; others went to the Netherlands; yet more ended up in Turkey and the Levant. But we turn our attention to those deportees who eventually found their way to Eretz-Israel. In the first half of the 16th century, in Galilean town of Safed, there congregated many of the Spanish 'exiles' - they or their children. What particularly distinguished this group was the fact that its members immersed themselves in Kabbalah (Jewish mysticism). It is not too difficult for us to see that this compulsive involvement with Kabbalah was in fact an attempt to escape from the miseries of everyday life into a charmed world which certainly caught their imagination.
Kabbalah had been around for some time; despite the protestations of its devotees that its main work, the Zohar, was composed by the Tanna Rabbi Shim'on bar-Yoĥai in the 2nd century CE, scholars maintain that its origins are to be found in Spain and in Provence (Southern France) during the 12th century. However, the leader of the Safed group, Rabbi Yitzĥak Luria [1534-1572], developed a whole new Kabbalistic system which inspired all his companions and followers. Kabbalah introduced (and re-introduced) many new customs. One custom that the Safed group introduced was inspired by the customs of Rabbi Ĥanina and Rabbi Yannai described above in the quotation from the Gemara. On Friday afternoons, as the sun was westering, the whole community (or rather all the males in the community!) would go out into the countryside around the town, already dressed in their Shabbat best, in order to greet the Queen-Bride Shabbat and escort her into town with song and dance. This custom of the Safed Kabbalists very soon became the ceremony of Kabbalat Shabbat that we hold in the synagogue before the Shabbat Evening Service. (The service as we now know it was arranged by Rabbi Moshe Cordovero [1522-1570] at Luria's request, and his brother-in-law, Rabbi Shelomo Alkabetz [1505-1576] added the famous hymn Lekha Dodi which he had composed.)
Now that we are clean and spruced up we are ready, at last, to receive Shabbat by lighting the Shabbat candles - which is the subject of the next Section.