How to Know the Higher Worlds, by Dr. Rudolf Steiner
Thanks to Daniel for introducing me to this excellent esoteric text full of such insightful passages as the following:
We must become accustomed to listening in such a way that we quiet our own inner life completely when we listen. For example, when someone expresses an opinion and another listens, agreement or disagreement usually stirs immediately within the listener. Often in such a situation we feel compelled to express our own opinion at once, especially if we disagree. However, on the path to higher knowledge we must learn to silence any agreement or disagreement with the opinions we hear. Naturally, this does not mean that we should suddenly change our way of life and strive to achieve this complete inner silence all the time. We must start with isolated instances that we choose intentionally. Then quite slowly and gradually, as if by itself, this new way of listening will become a habit. In spiritual research, we practice this new way of listening in a systematic way. As students, we should feel it our duty to set aside, as an exercise, certain times when we listen to the most contrary opinions, completely silencing within us all agreement and, especially, all negative judgments. Not only must we silence our intellectual judgment but also any feelings of disapproval, rejection,or even agreement. Above all, we must observe ourselves carefully to ensure that such feelings, even though absent from the surface of the soul, are not present in its inner-most depths. For example, we must learn to listen to the remarks of those who are in some way inferior to us, suppressing every feeling of superiority or knowing better.
How to Know Higher Worlds