True, pure and real emotion is so overwhelming that one feels an expansion in the centre of the chest that grows and continues to grow, issuing forth a physical sensation of pressure, an almost solid but fluid substance.
As it flows forth, the body becomes weak yet not weak, it melts and keeps its form. The emotional experience becomes the only experience in the conscious mind, while all things around become clearer.
All things are individual yet known in a sense to be one being, as in members of a family, separate individuals yet the family is one.
The sensation grows, if it is not stifled by a deliberate attempt to stop it due to the overwhelming power that takes over the person, until the person is left crying without cause or ability to stop.
This is the burning bush of Moses. The experience of true emotion burning in his heart without end or diminishment of his being. It was his understanding of all beings which made him stand apart. The face and manner of a person who has experienced this can be seen by some, but even if not recognised, a personal interaction with this person will leave one with a sense that they have been truly seen, understood and accepted, ultimately loved. And so, with this feeling towards all others, Moses was able to lead the Jews and they would follow.
His feeling towards all people must have preceded his experience of the burning bush, as it is necessary to already have this love and willingness in order to be so consumed. Then, you will need devotion, absolute abandon, and the willingness to have ones own character and life altered, in order for this experience to occur.
The human nature of desire to be individual and control ones life is the prevention of this experience. No matter how much one can love or accept others, if there is a thread of reluctance to allow oneself to completely dissolve, then that thread holds the ego to the body and the experience is prevented. If it occurs, that thought of individuality will cut the experience off.
The burning bush is within each person to the capacity that they are willing to become it. That a person is an individual is what prevents it from occurring. The comforting fact is that as one becomes consumed in this fire, the individuality remains, but it is the values and desires which make each person unique, that change.
One of the requirements to experience the burning bush is a release and relaxation of all physical tension in the chest but preferably the entire body.
Tensions, frustrations, aggravation in life, for whatever reason and cause, can cause the body and chest tense up. It is in the tension that we are prevented from the relaxation.
Abandon and freedom are really only possible when there is nothing to fear. The experience can be encouraged by awareness in the centre of the chest on an ongoing basis.