Etymologically regarded the word mysticism comes from the Greek myein, i.e., "closing the eyes." Mysticism thus primarily means a mental condition, in which one withdraws oneself from the outside world and in an act of introversion turns inward, by closing eyes, ears and mouth.
In addition mysticism always refers to something divine. Together with the above etymological derivative we can therefore conclude that mysticism represents an occupation with God or with the divine in oneself. A mystic is thus occupied with images and voices, which come out from the inside; the direction of motion is thus from inside to outside.
These circumstances are very beautifully represented in a vision of the Swiss mystic Nicholas von Flue. In this vision Nicholas sees the face of God, whose eyes ears and mouth are each pierced by a spear tip. If one imagines this very concretely, one comes to the conclusion that the challenge of such a human is it to close the ears, the eyes and the mouth for the purpose of not listening, not looking and not speaking anymore to the outside. Such a human is thus forced to become a mystic, i.e., to turn to one’s own interior world. If one follows this process, it will proceed from the inside outward – as the second three spear tips in Nicholas’s vision. They point from the head outward, thus from the inside outward.
With this symbolism the process of a mystic is very beautifully described: They turn inward, by closing mouth, eyes and ears, from which one experiences that something flows from the inside outward. This flow corresponds to the visions seen during the mystical process.
However, in the image it is actually God whose "extraverted sensation organs" are pierced. This means that the ability to meditate and to become a mystic rises from a divine center in the human soul. Nicholas thus became pulled into this divine inner process, so that in the long run he was not able to do anything else but live the life of a mystic. (Remo F Roth)