Guru and disciple: The Eternal Pair
In the vast majority of cases, a "Guru-disciple" relationship will have to take place for the Self to reveal itself. Very, very few disciples are able to realize Him on their own (without any spiritual master). They can realize Him without a Guru because they are spiritually very advanced from their very birth. Since this very rare kind of spiritual aspirant is not the rule but the exception, it will be excluded from my explanation.
There are two kinds of spiritual masters (Guru-s): False and true.
False teachers are the majority again... it is always the same story in this damned world, unfortunately. There are many subtypes of false Guru-s. By 'false' I mean a teacher who makes disciples waste their time. By 'true' I mean a teacher who makes disciples advance towards Self-Realization.
Among false teachers, there is first the most foolish category:
Guru-s who teach that no Guru is needed
This kind of teacher believes in individuality as the dominant force in attaining Self-realization. This is self-contradictory, because if any spiritual aspirant "as such" (i.e., as a limited individual) is capable of attaining spiritual enlightenment "on his own," why is the Guru teaching him that? The spiritual aspirant already knows this and can find the path to Self-realization on his own in that case. No instruction is needed.
I hope this is clear. Suppose you find a Guru who says that you are fully capable of attaining Self-Realization on your own (without his help). Then why does he even need to tell you that? He should assume that you already knew that. In this sense, this kind of spiritual teacher is super duper, because by stating that you don't need a Guru, they tacitly imply that they themselves, as well as their teachings, are useless. This being the case, what's the use of listening to them? There is no end to human imbecility. I am not saying that they are always bad or malicious. They may be good people, but with their talk about the Holy relationship between Guru and disciple they only add more confusion to the mind of an already confused spiritual aspirant. These kinds of teachers are useless then.
Guru-s who teach that all you need to do is "let it be"
This is another foolish type of false Guru. They are not necessarily bad either, just absurd. They teach that all spiritual aspirants should flow with the force of nature, of life, of God, etc. In short, "just let it be", "be yourself as you essentially are", etc. While these teachings can be given to amazing disciples who are on the verge of attaining Liberation, they cannot be given to the rest of the spiritual aspirants for the simple reason that they cannot just flow or just let it be, etc. That is why he is a spiritual aspirant and not a liberated person. Therefore, these kinds of teachers look "cool" and "impressive", but in the end they are useless because spiritual aspirants are again wasting their time on someone whose common sense has been lost.
It is common for spiritual aspirants to tell their entire life story to their Guru-s. For example, a spiritual aspirant may tell his teacher, "My wife cheated on me, and I feel so bad and frustrated!" The Guru will then say, "Let it be... be yourself!" One of the worst consequences of this kind of teaching is that the man may allow the worst portion of his ego to flow out and kill his wife. Instead of giving teachings appropriate to the level of the aspirants, this kind of teacher gives the most advanced teaching to all sadhaka-s. There is no common sense here.
A spiritual aspirant living in this karmic place known as the world comes across problems that he cannot solve by just letting them be. Of course, in the end it all has to do with spiritual ignorance and his mind, but such a spiritual aspirant has no real power to deal with such an obstacle at the stage of spiritual evolution he is in. "So, you have a mental cancer... let it flow!" This is absolutely stupid. The teacher should provide the disciple with the correct knowledge and some kind of practice that is suitable for him at that time. Telling him to "let it flow, just be" is not the proper teaching except for the case of highly evolved spiritual aspirants who obviously have no use for such a teacher because they already know that.
Guru-s who teach something crazy
Not all spiritual aspirants are intelligent enough. Some of them will be wrongly led by such teachers. This category of false Guru-s includes all those lunatics who "tacitly or openly" say that the Self will come to earth some day, or that the Self is far away in some spaceship, or that He is a cyborg living in a deep cave on Mars and similar crazy things. These kinds of Guru-s are rampant in the world today, unfortunately. As a result, I have personally seen many spiritual aspirants being led from one crazy idea to the next. Such teachers simply give free rein to their imagination until they and their disciples become mental cases. They have no scriptures to prove their point, of course. They only have "revelations." They are not necessarily bad, just crazy people.
Sometimes, one of these teachers is crazy enough to make his disciples commit suicide in the name of God, or out of fear of an impending apocalypse, etc. When this happens, you can be sure that the Guru is a complete psychopath.
They are not recommended at all, not only because sadhakas might end up in a mental asylum or even dead, but especially because they will waste their time again with such useless Guru-s.
Guru-s who seek to make money, fame and such things
Spiritual masters who have disciples just to make money, gain fame and such trivialities are nothing but beggars. They can be harmful too. Spiritual aspirants can learn some real things from them, but since money, fame, etc. are always in the way, such Guru-s are absolutely useless in the end. Their greed for money can reach the point where only millionaires can be spiritual aspirants who are fit for Self-Realization. All in all, do not waste your time with them. They usually teach in big organizations where only money matters. While I can understand that a Guru might charge his disciples a little because he needs to continue living in this world, if he charges too much or leaves out those who do not have enough money, he is not a real spiritual master. So, I am not saying that all Guru-s should follow the "free" mode, but the price of his teachings should be reasonable.
These teachers usually give expensive courses, extolling how good their courses are, etc. You can recognise them immediately, because according to them, after each course you should have the status of the greatest Vedic sage. This is cheating people. In reality, it is not possible. You will not gain Liberation in a jiffy, usually. It will usually cost you an arm and a leg, figuratively speaking, in terms of the magnitude of the effort. If Liberation were as easy as these teachers advertise, why is the world not full of liberated people? Another deception then, and more time wasted in the process.
Guru-s who seek to explain the Self through materialistic processes
This is not a modern invention, but such Guru-s are rampant now. They try to establish that you can reach Śiva by altering your brain processes, DNA and similar things. They always try to make you reach the divine Self through medical, scientific explanations, etc. These types of teachers might even be so obsessed with brain processes that they scan your brain while you are meditating and come to some stupid conclusion about how to attain Liberation. Their main characteristic is that they constantly try to reduce everything that is spiritual to the material sphere in some way. They are truly a pest!
There could be even more categories, of course, but the ones I mentioned are more than enough for now. All these fake Guru-s may be well-intentioned or malicious. Either way, they share one common characteristic: They make spiritual aspirants waste their precious time uselessly.
Then you have the real Guru-s:
Great Guru-s: Freed from both ignorance about the Self and intellectual ignorance.
Scholars: Freed only from intellectual ignorance.
Inferior Guru-s: Freed only from ignorance about the Self.
It is always advised to go for the Great Gurus first. But if you cannot find one, you should go for a scholar. With the help of a scholar, your intellectual ignorance will be removed, and this is 50% of your spiritual mission. Anyway, if you cannot even find a scholar, you should go for a lesser Guru, although this is not particularly recommended. But yes, something is better than nothing, as the saying goes.
The common feature of true Guru-s is that they all consider the Self to be divine and to reside "right here and now in you." So, you can start your spiritual path solidly with them, because you know through their teachings that the Self is here and it is possible for you to realize It. Spiritual enlightenment (also known as Liberation) is then real and possible.
Of course, genuine Guru-s teach you everything about the Self through different approaches and methods, but all of them will always point in the direction of the Self. Some of them may initiate you on the spiritual path. Others may teach you the truth according to a particular philosophical system. Still other genuine teachers will lead you directly to Liberation through their special instructions, etc. In spite of their differences, they share the common feature that they will not make the spiritual aspirants waste their time uselessly. On the contrary, their help will become absolutely indispensable.
Excerpt from the book: Spirituality - Volume 1.
Link to buy this book: https://a.co/d/fstoOsX
Link to watch a video series about this book on YouTube: https://youtube.com/playlist?list=PLIGvnPY5xTKOcZtCt6Z25c5yESfh9Md4v&feature=shared