According to Jewish doctrine, repentance is the prerequisite of atonement. Yom Kippur, the day of atonement, derives its significance only from the fact that it is the culmination of the ten penitential days with which the Jewish religious year begins; and therefore it is of no avail without repentance Though man ought to be penitent every day, the first ten days of every year are the acceptable time announced by the prophet Isaiah: "Seek the Lord while he may be found, call upon him while he is near".