Thought itself must deny itself. Thought itself sees what it is doing and therefore thought itself realizes that it has to come of itself to an end. … - Jiddu Krishnamurti

Why does the brain retain the memory of the hurt from yesterday?

Just observe what you are. What you are is the fact: the fact that you are jealous, anxious, envious, brutal, demanding, violent. That is what you are. Look at it, be aware; don’t shape it, don’t guide it, don’t deny it, don’t have opinions about it. By looking at it without condemnation, without judgement, without comparison, you observe; out of that observation, out of that awareness comes affection. Now, go still further. And you can do this in one flash. It can only be done in one flash — not first from the outside and then working further and deeper and deeper and deeper; it does not work that way, it is all done with one sweep, from the outermost to the most inward, to the innermost depth. Out of this, in this, there is attention — attention to the whistle of that train, the noise, the coughing, the way you are jerking your legs about; attention whereby you listen to what is said, you find out what is true and what is false in what is being said, and you do not set up the speaker as an authority. So this attention comes out of this extraordinarily complex existence of contradiction, misery and utter despair. And when the mind is attentive, it can then give focus, which then is quite a different thing; then it can concentrate but that concentration is not the concentration of exclusion. Then the mind can give attention to whatever it is doing, and that attention becomes much more efficient, much more vital, because you are taking everything in.

Surely, the violence and the entity who says, "I must change violence into non-violence", are both the same. To recognize that fact is to put an end to all conflict, is it not? There is no longer the conflict of trying to change, because I see that the very movement of the mind not to be violent is itself the outcome of violence. So, the questioner wants to know why it is that he cannot go beyond all these superficial wrangles of the mind. For the simple reason that, consciously or unconsciously, the mind is always seeking something, and that very search brings violence, competition, the sense of utter dissatisfaction. It is only when the mind is completely still that there is a possibility of touching the deep waters.