Self-knowledge knowledge or Brahma Gnana or Atma Gnana cannot be transmitted neither from the outside nor from any Guru.+

The Soul, which is present in the form of the consciousness is primordial Guru, shows the ways to merge with it. There is no other Guru other than the Soul.

There is no need for a Guru in the path of wisdom.  The Guru is useless so long as the ultimate truth is unknown, and Guru is equally useless when the ultimate truth or Brahman has already been known.

If you indulge in worshipping and glorifying Gurus of the past or present,  surrendering to Guru, blocks you from realizing the truth, which is beyond the form, time, and space.       

Vedas bars human worship: ~

Translation 3

"They are enveloped in darkness, in other words, are steeped in ignorance and sunk in the greatest depths of misery who worship the uncreated, eternal Prakriti -- the material cause of the world -- in place of the All-pervading God, But those who worship visible things born of the Prakriti, such as the earth, trees, bodies (human and the like) in place of God are enveloped in still greater darkness, in other words, they are extremely foolish, fall into an awful hell of pain and sorrow, and suffer terribly for a long time. :~  (Yajur Veda 40:9.)

Then why worship and glorify the Gurus and Yogis (human form)   in place of God when Veda bars such activities and it also warns people who indulge in such activities are enveloped in still greater darkness, in other words, they are extremely foolish, fall into an awful hell of pain and sorrow, and suffer terribly for a long time.

Swami Vivekananda said: ~   You have to grow from the inside out. None can teach you, none can make you spiritual. There is no other teacher, but your own Soul.”

People study  Advaita under some guru and they under the delusion and conclude that they declare:~   "I-Am-Brahman",   but they fail to realize the fact that   Brahman is everywhere and in everything! The existence of Brahman is not limited to his physical identity, because, it is the very essence of form, time, and space.

That is why Buddha said: ~ Believe nothing because a wise man said it, Believe nothing because it is generally held. Believe nothing because it is written. Believe nothing because it is said to be divine. Believe nothing because someone else said it. But believe only what you, yourself judge to be true. (from The Mystic Vision Compiled by Andrew Harvey and Anne Baring)

Sage Sankara clearly indicates in Viveka Chudamani (2) that the Knower of the Atman (A Gnani) "bears no outward mark of a holy man" (Stanza 539).  

A Gnani wears no signs which means he does not identify himself as Guru or teacher or Swami. 

Thus, one should not go behind these the Self-declared Gurus and yogis who speak of ripeness and effort, of merits and achievements, of destiny and grace; all these create addiction and yield only a hallucination. Instead of helping, they become an obstruction to realizing the truth, which is beyond form, time, and space.  

Sage Sankara page 482: On Gnani: "The knower of Brahman wears no signs. Gives up the insignia of a monk's life…his signs are not manifest, nor his behavior." 

When the knower of Brahman (Gnani) wears no signs it means he does not identify himself as Guru or yogi or teacher or Swami. 

Thus, those who identify themselves as holy men are not Gnanis. Thus, those Gurus who promise Self-realization are taking the seekers for a ride.  

Sage Sankara clearly 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) VivekaChudamani v 56, pg 25.

Self-knowledge knowledge or Brahma Gnana or Atma Gnana cannot be transmitted neither from the outside nor from any Guru. Guru of everyone is only the Soul, the Self that is always revealing on its own.

The grace of the Guru is only that Self-awareness that is the nature of the Soul. It is the inner consciousness by which it is unceasingly revealing its existence. This revelation is always going on naturally in every serious seeker." 

Self-knowledge knowledge or Brahma Gnana or Atma Gnana is given neither from the outside nor from another person. It can be realized by the seeker himself. The Gnana Guru of everyone is only the Soul the innermost Self, that is always revealing its own is the seeker who is receptive and serious in quest of truth.:~Santthosh Kumaar