We bathe and cut our hair [before Rosh Hashanah] on the strength of the Midrash. Rabbi Simon said: It is written, “For who is a great nation, etc.” (Devarim 4:7). Rabbi Chanina and Rabbi Yehoshua say: Which nation is like this nation, which knows the character of its G-d, that is, His ways and His laws? For the way of the world is that a person who has a judgment [pending against him] wears black and wraps himself in black, lets his beard grow and does not cut his nails, because he does not know how his judgment will come out. But Yisrael are not so: they wear white and wrap themselves in white, shave their beards and cut their nails, and eat and drink and rejoice on Rosh Hashanah, because they know that HaKadosh Baruch Hu will do a miracle for them. Therefore it is the custom to cut the hair and wash clothes on Erev Rosh Hashanah, and to serve many courses on Rosh Hashanah.