With twenty-one syllables a man reaches the sun (and death), for the sun is the twenty-first from here; with the twenty-second he conquers what is beyond the sun: that is blessedness, that is freedom from grief.

In plain words: With twenty-one syllables a person reaches the sun, which is the twenty-first world from here and also stands for death. With the twenty-second syllable he goes beyond the sun, to a place of happiness with no sorrow.