Since I will be referring to Mysticism and quoting from Christian mystics, it might be best to define my terms.
Definition of Mysticism
I can think of no better authority on mysticism than the Anglican writer Evelyn Underhill. In one of her shorter books, she gives the following definitions:
Mysticism is the art of union with Reality. The mystic is a person who has attained that union in greater or less degree; or who aims at and believes in such attainment.
Christian Mysticism
For a Christian mystic, that “Reality” is God as revealed in the Holy Scriptures. My own definition would be that:
Christian mysticism is the study of, pursuit of, and the experience of oneness with God in and through Christ.
What Christian Mysticism is Not
The Christian mysticism I will be referencing has nothing to do with magic, astrology, crystals, alchemy, or the bizarre. Even dreams and visions are seen as suspicious. They are not essential to Christian mysticism, and can even be hindrances.
All are Called
Every Christian is called to this experience of oneness with God. Everyone is called to the mystic way. In fact, I think Karl Rainer might be right, “the Christian of the future will be a mystic or will not exist.”