3  Manu,  II.  83.  The  mystic  syllable  OM  {aum)  is  the  constant  sign  of  that  worship  of
unity,  which  pervades  Hindu  thought.  Burnouf  {Sansk.  Diet.)  refers  it  to  avam,  as  from  the
Zendic  ava  {this  one),  marking  existence,  —  "  He  that  is  to  be."  But,  more  probably,  it
was  a  combination  of  the  initials  of  the  three  main  elements  of  Vedic  deity,  —  Agni,  Varuna,
and  the  Maruts.  The  Mandukya  Upanishad  refers  the  three  letters  to  Brahma,  as  wak-
ing, dreaming,  and  sleeping ;  in  other  words,  as  manifested  outwardly,  as  manifested  to
himself,  and  as  ;<«manifested,  in  the  unity  of  his  essence ;  while  the  whole  word,  abolishing
the  distinctions  of  the  letters,  represents  his  absolute  nature.  The  formula  of  the  Bhaga-
vadgita  is  Om  tat  sat,  or  "  God  is  tliat  [i.e.,  the  universal]  reality."  Later  still,  the  same
syllable  unites  Brahma,  Vishnu,  and  Siva  in  a  trinity.  It  expresses  the  Buddhist  oneness
of  "Saint,  Law,  and  Congregation."  It  is  the  prelude  to  all  Buddhist  formulas  of  prayer.
To  the  Brahmanic  Om  tat  sat  corresponds  the  Thibetan  Om  mani  padme  hSm.  In  sum,
this  sacred  word,  adored  throughout  eastern  Asia,  fully  represents  the  continuity  of  Hindu
religious  sentiment,  and  its  devotion  to  ideal  unity,  through  all  phases,  epochs,  and  results.
4  Mwidaka   Upanishad,  II.  i.  10;  ii.  5.
314  RELIGIOUS    PHILOSOPHY.
