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.
A Guru is needed in religious and the yogic path. There is no need of a Guru in to acquire Self-knowledge or Brahma Gnana or Atma Gnana.
Unless you realize the Self as the Soul, you are all blinded by the dualistic illusion.
The Guru who pretends he to be Self- realized and plays with the emotions and sentiments of the seeker is a fraud, not a Gnani.
All the Guru Parampara is for the religious people. There is no need of a Guru who wants to tread the path of wisdom.
Even swami Vivekananda was Ramakrishna Paramahansa disciple. Swami Vivekananda himself 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.”
There are two kinds of audiences - the ordinary ones who desire the transitory heaven and other pleasures obtained as a result of ritual sacrifices, and the more advanced seeker who seeks to know the ultimate truth or Brahman. The Guru and Guru paramparas are meant for the first audience, to help lead its followers along the way. However, there is no need to follow any parampara and follow any Guru those who wish to realize the truth which is beyond the form, time, and space. We should not mix religion with spirituality because the religion is based on the ego and spirituality is based on the Soul. The religion is concerned with its paramparas, not truth whereas the spirituality is concerned only with the truth, which is beyond the form, time, and space. The religion is not spirituality.
Sage Sri, Sankara: ~ "Though I wear these robes of a Sanyasin, it is only for the sake of bread." (Select Works of Sage Sri, Sankara" also his commentary on Brihad)
Thus, the above passage proves that all those who were the sanyasin robes are wearing it for the sake of bread belongs to the religion; they are nothing to do with the Self-knowledge or Brahma Gnana or Atma Gnana. There is no need to criticize and condemn the Gurus, yogis and swamis because they are needed for the welfare of ignorant mass in the dualistic world.
Sage Sri Sankara in Viveka Chudamani (2), states that the Knower of the Atman (i.e., a Gnani) "bears no outward mark of a holy man" (Stanza 539).
It means the Gurus, Swamis, and Yogis who identify themselves as holy people are not Gnanis.
Those who are seeking the truth need not follow any Guru or any teaching.
The one who thinks himself as a Guru and the one who thinks himself as a chela (disciple) will not be able acquire Self-Knowledge or Brahma Gnana or Atma Gnana, because both of them accepted themselves as the body. And all their understanding, practices, knowledge are based on the false Self (ego or you). Therefore, the Guru –Shisya concept is a great obstacle in the pursuit of truth. That is why Sage Sri, Ramana Maharishi never accepted himself as a Guru or accepted anyone as his disciple because he was fully immersed in his true Self, which is formless consciousness. There was no division in his consciousness even though he was in the midst of division or duality.
The consciousness is like the ocean. Love is like a wave. When waves love each other then they become one with the ocean.