Lord Krishna :~ It is not yoga but the philosophic truth.+

Sage Sankara said:- Neither by the practice of yoga nor philosophy, nor by good works nor by learning, does liberation come, but only through the realization that Atman and Brahman are one in no other way. (1) Vivekachoodamani v 56, pg. 25

Lord Krishna confesses that the oldest wisdom of India (our true Advaitic wisdom) has been lost: people misinterpret and falsify it today as they did then. It is not yoga but the philosophic truth. But nobody knows it. The teachers of philosophy and leaders of mysticism or religion do not want to inquire into truth and have no time for it. (Gita –Chap- IV-v.2)

In the Gita Chap.IV where Lord Krishna says: ~ "This yoga has been lost for ages." the word yoga refers to Gnana yoga, not other yogas: the force of the word this is to point this out.

Lord Krishna describes some of the other yogas, but devotes this chapter separately to Gnana Yoga. So, one sees even in those ancient days, people did not care for Advaita; they wanted religion; hence, Gnana got lost.

That is why Krishna calls it "the supreme secret." Krishna points out that the yoga must-see is "Brahman in action."

Gita Chap.IV: "He who achieves perfection in Yoga finds the Self in time." This means that after his yoga is finished, he begins the inquiry into the ultimate truth, and in due course, this inquiry produces the realization of the universal Spirit as the result.

When a yogi finds yoga inadequate and useless to realize the Self, he must drop yoga and take up the path of Gnana.

Swami Vivekananda: ~ ‘Jñāna Yoga is divided into three parts. First: hearing the truth--that the Atman is the only reality and that everything else is Maya. Second: reasoning upon this philosophy from all points of view. Third: giving up all further argumentation and realizing the truth.

This realization comes from being certain that Brahman is real and everything else is unreal.

Lord Krishna says Ch. V:~ “Those who know the Self in truth.". The last two words (tattvataha) are usually ignored by pundits, but they make all the difference between the ordinary concept of God and the truth about God.

Sage Sankara says: - Yoga is not the means of liberation (page 132-133 - Commentary on Brhadaranyakopanishad.

In Sutra Bashya and Manduka: - The Samadhi and sleep are identical.

Brihad Upanishad does not advocate Samadhi.

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

Panchadasi: - The impossibility of yoga arrives at a successful end to its practices. (P.509 v, 109)

Bhagavan Buddha gave up his austerities of yoga as impossible and useless. (Page.70/71 "Buddhism in Translation” by Warren)

Bhagavan Buddha got enlightenment only after he gave up Yoga. Unless one exercises their reason--there is no chance of getting the truth.

There is no need for any practice to realize the ultimate truth, or Brahman or God in truth. Perfect understanding and assimilation of ‘what is what’ is very much necessary to realize the ultimate truth or Brahman, or God in truth. :~  Santthosh Kumaar