Two for One

While Yom Kippur is a very serious day of introspection, it is also regarded as a joyous day, since God annually forgives the Jewish people. As fasting is not conducive to celebration, the day prior to Yom Kippur is considered a festive day, where we are commanded to eat and rejoice. Apparently, it takes two days to fully absorb the power of Yom Kippur.