#1. LIBERATION FROM SUFFERING RELATED TO EXTERNAL MATTER
Grab a hammer. You can see that the hammer is not you. Bang the hammer lightly against something. You can see it's empty (that it's not self and it's impermanent, impermanent meaning temporary, easily destroyed). The hammer can be damaged or destroyed and there is no suffering. A clever man might say, "There is no suffering because the hammer has no pain receptors." But we can easily find ourselves suffering from external objects. Imagine your favorite object in your home, like a treasured family photo, family heirloom, jewelry (especially a wedding ring), expensive electronics, musical equipment, memorabilia, clothes, and cars. Now imagine these things being destroyed. You would suffer! Why? These objects have no pain receptors. And you should know they are empty (meaning impermanent and not self), so why is there suffering? There is suffering because you do not really see their impermanence; you do not want to believe it, not all the time. And you don't really understand this until what you crave is ripped away. And then you can see how you regard them as self, as "mine". When they are destroyed, suffering results in the context of impermanence, from attachment: "What is mine is gone!" But it was never yours to begin with, because mine and yours are just ideas which have no bearing on physical reality; reality doesn't care what you think you do or don't deserve.
A foolish person might dispute this, having lost his expensive jewelry, electronics, or even things like family photos that we tend to think are appropriate things to cling to. In his deluded state of mind, he might say, "What you say doesn't change anything! What I have is still gone and there is still this feeling! What you say doesn't make this feeling go away! It's still there!" He blames the world for his own craving. He should observe the emptiness of things, but he does not. It's not that he can't look, but chooses not to. And the funny thing is that this can happen to Buddhists too. They have the view of universal notself and impermanence, but when their car breaks down, their electronic toys break, their wedding ring goes missing, they get angry or upset.#2. LIBERATION FROM SUFFERING RELATED TO INTERNAL MATTER
Take your hand. Look at it. You can see that the hand is not you, although many people might think of it as "a part of me", because it's a part of the body. If clearly seen, this too is empty (not self and impermanent). The hand can be easily damaged and destroyed. If we bang the hand against a hard surface, unlike the hammer there is pain, and for most of us, also suffering. But if we see clearly, we see the emptiness of the hand and the rest of the body: there really is no such thing as "suffering of the body". Suffering is in the mind. Pain is a bodily sensation which we are opposed to, just as pleasure is something we desire. "Suffering," is the mental state of craving for pleasurable or stimulating sensations and aversion to painful or limiting ones. We can regard the whole body as not self. There is a distinction to be made here, however: We can think of the body as self (merely an idea or opinion), which is different from seeing it that way, which takes concentration or meditation. A person can have the intellectual view, "The body is not self," but if you pour gasoline on him and set him on fire, he would run around flailing because he lies to himself and lacks concentration. For one who is deeply concentrated -- monks (or Indian and Asian sages) who regularly practice meditation and deep mindfulness, the body is just a puppet which houses the mind and pain is merely a sensation of the puppet, which does not afflict the mind. For such a being, the outside world is not a burden, only hindrances of the mind are a burden.
A foolish person might dispute this, though, feeling pain from sickness, old age, or injury, and he might say, "What you say doesn't change anything! I still feel suffering because of the body! There is still this feeling! What you say doesn't make this feeling go away! It's still there!" He blames the body for his own craving. He should observe the emptiness of the body, but he does not. It's not that he can't look, but chooses not to.#3. LIBERATION FROM SUFFERING OF THE MIND
In your mind, imagine a hammer slamming against another object. You can see that you are not that fabricated hammer or the fabricated object, although many people might think of it as "part of me," because it's within the mind. Moreover, if you look clearly, you see that not only are the objects of consciousness impermanent and not self, the whole thing -- consciousness -- is a fabrication that is impermanent and not self. Still, though, as with the realization of emptiness with regards to internal matter, there is a difference between thinking of the mind as not self and seeing it that way. It is very easy to go around falsely claiming to have Buddha-nature, Buddhahood, Nirvana, and supreme enlightenment merely because you found an amazing idea about the mind. You could go around, falsely proclaiming enlightenment, being a self-ordained monk (like Jeffrey Brooks aka "jhanananda"), try to start a cult (and with such clever ideas you might succeed!), or at the very least, you might just start really long threads on Buddhist forums which don't need to be made, arguing with people when such arguments are not needed, not helping yourself or others find freedom from suffering. All because you have this "idea"... But you don't really see things that way. So, while you may have a very powerful samadhi, so much so that you have great mental clarity and no longer experience physical pain, you still experience suffering from attachment to the formless, from regarding the mind as "mine." But with the highest concentration, the deepest meditation, you can see to see the self outside the mind, and thus realize the unconditioned, being free from all self-perception and suffering, mental affliction, and pain. Because if you see your self outside the mind (simply another way of saying "seeing mind as empty -- impermanent and void of self"), what hindrances are there? What suffering is there to be relieved? What enlightenment and ignorance is there? This is where the four elements find no footing, where one finds final release. Not "where the four elements cease," not where self is augmented or annihilated; it's a place that has been here all along that you just didn't see, which is defiled and free from defilement, but itself is forever pure and clean. It is consciousness without feature, immovable but capable of adapting to motion; it's metaphorically compared to diamonds and light.
And once again, a foolish person might dispute this, though, feeling mental suffering for all sorts of reasons, and he might say, "What you say doesn't change anything! You are only using the mind in a different way! And I still feel suffering because of the mind! There is still this feeling! What you say doesn't make this feeling go away! It's still there!" He blames the mind for his own craving. He should observe the emptiness of the mind, but he does not. It's not that he can't look, but chooses not to.
This is all very straightforward, as I see it. It's so plainly obvious. It's not elaborate or clever or tricky. It just requires sincerity, thoughtfulness, and the IQ level of Homer Simpson or higher. So, when some people ask, "Why doesn't the Buddha make everyone enlightened?" they ask that question with a wrong understanding. What they should more appropriately ask is, "Why does anyone want to suffer? Why doesn't everyone want to be enlightened?" If they do want to be free from suffering and do want want enlightenment, if they simply turned their minds inward and away from suffering and away from conceptual-proliferation, it is possible. Did anybody here find this helpful? If not, please let me know. I'm extremely open to criticism, insults, slander, people throwing tomatoes and other various rotten fruits & vegetables, etc..
Also, for the record: I am not "enlightened." I am somewhere between #2 and #3, although sometimes even #1 gives me a problem. At times, I find this form of concentration gives me clarity regarding sensual desire, a great (but not yet infinite) endurance to overcome physical pain, and a great (but again, limited) capacity for overcoming mental suffering. But I am headed in the right direction, which is the important thing.