Bhagavad Gita Chapter 6 Verse 39
भगवद् गीता अध्याय 6 श्लोक 39

एतन्मे संशयं कृष्ण छेत्तुमर्हस्यशेषतः।
त्वदन्यः संशयस्यास्य छेत्ता न ह्युपपद्यते।।6.39।।



हिंदी अनुवाद - स्वामी रामसुख दास जी ( भगवद् गीता 6.39)
।।6.39।।हे कृष्ण मेरे इस सन्देहका सर्वथा छेदन करनेके लिये आप ही योग्य हैं क्योंकि इस संशयका छेदन करनेवाला आपके सिवाय दूसरा कोई हो नहीं सकता।


Shri Vaishnava Sampradaya - Commentary

No matter how much one may ever so enthusiastically embark on  the  path  of
yoga or the science of  the  individual  consciousness  attaining  communion
with the ultimate consciousness; if one lacks the  sufficient  determination
to maintain the persistent application  of  regulated  discipline  the  mind
will inevitably be distracted and deviate and one will fail  to  succeed  in
reaching perfection in yoga. What will be the fate of such  a  person?  Will
they perish like a divided cloud in the sky leaving the  rest  behind  while
failing to unite with the cloud in front of it  in  the  distance?  What  is
meant by double loss? The word apratistho means unfixed  situation  and  the
words vimudho brahmanah pathi means baffled due to ignorance of the  Brahman
or the spiritual substratum pervading  all  existence  which  is  the  first
cognition on the way to achieving enlightenment.

The first loss is failure to secure svarga loka or the heavenly planets  for
executing the appropriate actions.  Prescribed  Vedic  activities  performed
with the goal of residing in svarga loka liberally reward ones efforts  and
allows one to enjoy heavenly delights for as long a  time  as  ones  merits
warrant. But actions performed by persons without such intent do not  enable
a person to reside there hence one forfeits  the  opportunity  for  heavenly
pleasures. The second loss is ignorance of the path  of  the  Brahman  which
includes  performing  selfless  actions  without  desire  for  reward  while
contemplating on the atma or soul. But the person who  fails  to  pursue  it
consistently and steadfastly will deviate and stray away and  will  lose  in
both instances. So Arjuna wants Lord Krishna to alleviate his doubts.