Brihad Upanishads: ~Even yoga cannot give perfect concentration, and the only way to gain it is philosophical realization.+

Manduka Upanishad:~ Yoga is in the sphere of duality and is unnecessary to one who knows non-duality.

Brihad Upanishads: ~Even yoga cannot give perfect concentration, and the only way to gain it is philosophical realization. This confirms Manduka Upanishad’s statement that yoga can no more succeed than the ocean can be emptied with a blade of grass. (Page ~133- first para)

Yoga and Samadhi are not the goals but a means to an end, i.e. Gnana. Samadhi in itself is useless because the mind is withdrawn, and there is no memory of it until after it is over and one returns to waking state.

Yogi who attains mind control: it is only sleep. The world must be seen before you can know its true nature in Gnana. The yogi who shuts it out thereby deprives himself of the opportunity to achieve Gnana.

BRIH. Upanishad: ~ "Yoga does not yield truth or liberation."(page 32).

The Gnani sees the essential universal unity and the multiplicity of objects simultaneously. The person in deep sleep or Samadhi leaves out the objects and sees the essence; hence he has not the full Gnana. There was no permanent cure however without Gnana, and Yoga does not yield Gnana.

Sage Sankara in the commentary to "Brahma Sutras:- "The highest beatitude is not to be attained by Yoga." (Sacred Books of East Series page 298 Vol. 1.) And he also says Samadhi is the same as sleep (p.312)

~this indicates that yoga is not the means to self-realization. And yogic Samadhi is not nondual awareness. : ~ Santthosh Kumaar