I would like to use this post to clear some common wrong understandings.
1. Wrong understanding regarding a purified mind:
People with their imagination has fantasized a purified mind as something similar to:
Pure water with impurities. Or pure gold with impurities. Or like a diamond in a box and only that box is covered with impurities. Or like a mirror only reflects what shines upon it. Or like a moon always shines but only temporarily got covered by dark cloud. Or like a man with good eyes but his eyes got covered by a pair of bad spectacles.
In other words: They fantasize that the purified mind is always there inside each of us, separated from the impurities, not affected by the impurities. The purified mind only needs to know, that’s all.
So, people with such fantasy starts to see such a purified mind as NOT impermanent, pure, safe, NOT suffering. Then, people with such fantasy starts to consider such purified mind as themselves, shouting “Yay, that’s has been always me!” or “That’s belongs to me forever” or “That’s always inside me, timeless.” Then, people with such fantasy starts to consider such purified mind to be the same as Nibbāna.
The important thing is: We need to realize “to know” is a verb. A verb means: it’s a process. And a process means: it’s conditioned, it can NOT happen without supporting conditions. So, when the supporting conditions are not there, what happens? Answer: the process stops.
Now, when the process “to know” stops, the purified mind also stops being a purified mind. It becomes “a purified mind that does not know.” There, now anyone in their right mind can see for themselves, purified mind is impermanent. So, a purified mind can NOT be considered as self. There, of course, anyone in their right mind can also see for themselves, purified mind is NOT Nibbāna because Nibbāna is NOT impermanent.
For anyone still has doubt and still cannot abandon the fantasy idea that there exists a purified mind inside himself that always knows without supporting conditions, maybe they should ask themselves: Can they know anything without coming into contact?
For those people, my suggestion is: MN38 and MN14 are of very good help here.
In my opinion, it seems to me that such fantasy coming from a mind that is lazy. The reason is: with such fantasy, people all over the world no longer needs to practice the Noble Eightfold Path, their purified mind has always known and experienced Nibbāna, for all time, without any interruption.
2. Wrong understanding regarding reading secondary sources outside EBT:
There is also a misunderstanding when some teachers say something like “Nibbāna can be found inside you” or “Nibbāna is already inside each of us.”
I think the original message should be: “the capacity/potential to realize the Nibbāna, that specific capacity/potential is inside each of us.”
That message seems to be misunderstood when presented in another shortened form: “the capacity/potential to realize the Nibbāna inside each of us.”
3. Wrong understanding regarding faith toward favorite teacher/guru:
There is also a misunderstanding that you can place certain teacher/guru in a place higher than the Buddha. Then use their words to override the words of the Buddha in the EBT. We don’t have high confidence that such teacher/guru is really at arahant level but we DO have very high confidence that the Buddha and his disciples are at arahant level and their words are recorded in the EBT. If anyone does such thing, he/she is putting an unverified pupil above the verified teacher. I don’t think people will agree that such action is wise.
4. Wrong understanding regarding Nibbāna as nothing at all:
There is also a misunderstanding that Nibbāna is nothing at all or it does not even exist. It’s a Dhamma, a Reality, a real and verifiable state. Nibbāna was declared by the Buddha in the 3rd Noble Truth. However, it does not exist as the way a run-of-the-mill person so far has always imagined.
The difference with the neti-neti school (coming from tát tvam ási (That thou art - That you are)) is: The Buddha taught the Noble Eightfold Path to guide us to Nibbāna, which is not Self. Meanwhile, the neti-neti school holds a view even from the beginning that what remains after negation is the Self, before their practice of meditation. Side note, the following is my personal opinion so I am not open for debate right now on this: At the highest, with their meditation practice, anyone with such view will only be able to reach the formless realm of the Nothingness sphere.
5. Wrong understanding regarding logic and reasoning:
There is also a misunderstanding that we don’t need logic and reasoning. Logic and reasoning help us to choose the correct path, to separate the wholesome from the unwholesome, to separate the fool from the wise. I suggest anyone has such unhealthy doubt to look up in dictionary to know how people defines a person who denies logic and reasoning; or a person who denies solid evidence presented to him. I don’t see anywhere that the Buddha encourages us to abandon logic and reasoning while listening to his teaching.
Closing:
If after reading this post, anyone got questions pop up in their mind such as: Hmm, so now I am not too sure, do I have a self? So, you are telling me, I don’t really have a self? Do I actually currently exist right now? So, after all, do I got illusion, am I dreaming, do I not currently exist? Or putting up such question like: does the Buddha exist before/after his parinibbāna? Then I suggest that person please read again MN2 very carefully and thoroughly many times.
Thank you for your time reading this post. 
Note: Please kindly only give comments with focus on the EBTs, without including what are considered later sources. Also, I presented my points in a coherent logic that can be backed up by EBT, so normally, I expect other people to kindly do the same without relying on personal belief or appealing to feeling/emotion.