Bhagavad Gita Chapter 17 Verse 27
भगवद् गीता अध्याय 17 श्लोक 27

यज्ञे तपसि दाने च स्थितिः सदिति चोच्यते।
कर्म चैव तदर्थीयं सदित्येवाभिधीयते।।17.27।।



हिंदी अनुवाद - स्वामी तेजोमयानंद
।।17.27।। यज्ञ? तप और दान में दृढ़ स्थिति भी सत् कही जाती है? और उस (परमात्मा) के लिए किया गया कर्म भी सत् ही कहलाता है।।


Brahma Vaishnava Sampradaya - Commentary

The word SAT denotes creation and eternal goodness. The  pranava  refers  to
the first breath OM which is vibrated  at  the  commencement  of  all  Vedic
rites from the root word prana  meaning  breath.  Properly  pronouncing  the
pranava  OM  as  AH--OOOH--MMMMM  while  comprehensively  understanding  its
meaning without the slightest desire for rewards, by  performing  yagnas  or
propitiation and worship to the Supreme Lord  with  devotion  and  tapah  or
austerities and danam or charity as matter of duty,  by  japa  chanting  the
holy names of the Supreme Lord Krishna:
Hare Krishna Hare Krishna Krishna Krishna Hare Hare
Hare Rama Hare Rama Rama Rama Hare Hare
With great respect and love as well as the names of any  of  His  authorised
incarnations  and  expansions  as  revealed  in  Vedic  scriptures  are  all
considered SAT. Thus  by  duly  initiated  Vaisnava  brahmanas  evoking  the
sacred sound vibrations OM TAT SAT, the Supreme Lord is  verily  propitiated
and worshipped.

The Rig Veda confirms that yagnas  that  are  performed  for  the  exclusive
satisfaction  of  the  Supreme  Lord  without  the   slightest   trace   for
expectation of rewards and are  designated OM TAT SAT. The Vedas call  these
three divine sounds the performers of Vedic rites due to the fact  that  the
potency of vibrating OM TAT SAT perfects any defects,  insures  success  and
pleases the Supreme Lord granting communion with Him.