With every mental impulse, your body throws off particles of energy. Strong mental impulses produce a larger quantity of these particles. And how far these spread is largely dependent on the together-play of your physical vitality, with the strength of the emotion or mind-state. Now, when you have trained to be sensitive towards finer matter, you will be able to perceive this energy field spreading away from your body. Thus, even if some mind-state of anger or greed, etc. is terrorising you, if you can become aware of this energy, the negative emotion will be quickly worn away by the interference of the higher mind-state of interest which naturally arises when you perceive this energy field.
Gradually your interest in this subtler and loftier experience grows stronger than your desire to get, or your desire to hurt. Progressively, as you begin to enter deeper and deeper into this world of finer matter, you may begin to see reflections of memories related to that mind-state of anger, or greed, or whatever; in there. And with time, you may then also learn to look around in this field of perception, and besides seeing images of for example, the person who has hurt you; acquiring further distance, you might be able to perceive other things. Naturally you should look for something that gives greater confidence to your mind, so that you may learn to remain for longer in this sphere. Thus you might perceive, amidst images of the person who you perceived as your enemy, some image of a friend. And, if you, for example follow the Buddhist path, you then might feel inspired to build up some meditation on loving kindness, or universal, unconditional love, that is, love which knows no barrier.
Accordingly, you would try to develop further, the good feelings that would well up naturally when perceiving your friend, or the person that you admire. And when you succeed in making grow this good feeling, and this good mind state, than you would make experiments, as to whether you can broaden your mind to be able to feel these feelings, or to remain in this superior mind state also while perceiving people that do not naturally trigger this kind of mental condition. If you can do that, you will try further and further, how far you can push the limit, to ultimately include also people who have harmed you or who you had difficulties with in life. Thus you train yourself to become a superior person who stands above the sense-sphere world, even in difficult conditions.
The process that has been described in here, of course may be triggered also in various other ways. Because obviously many people will not be able to start off straight away with the perception of energies. Thus, the more traditional starting point will be, to wrestle with the strong emotion by the use of certain phrases, which are used somewhat in the same manner as a prayer. Praying, or vigorously reciting phrases like “May I be free from all evil states of mind”, or “May I be happy and free”, or even “May the power of the Buddha protect me from all evil”, or similar phrases, can throw the mind into a meditative state, in which it gradually lets go of its trouble, and unfolds into higher things or higher regions.