Few words indeed have been used in such a vague, indefinite sense as Mysticism. Its etymology does not determine its meaning. A μύστης was one initiated into the knowledge of the Greek mysteries, one to whom secret things had been revealed. Hence in the wide sense of the word, a Mystic is one who claims to see or know what is hidden from other men, whether this knowledge is attained by immediate intuition, or by inward revelation. In most cases these methods were assumed to be identical, as intuition was held to be the immediate vision of God and of divine things. Hence, in the wide sense of the word, Mystics are those who claim to be under the immediate guidance of God or of his Spirit.
Therefore, leaving behind the elementary doctrine about the Christ, let us press on to maturity, not laying again a foundation of repentance from dead works and faith in God,—Hebrews 6:1.