The Adornment of the Spiritual Marriage, by Jan van Ruysbroeck, , at sacred-texts.com
If, further, this good man would become an inward and ghostly man, he needs must have three further things. The first is a heart unencumbered with images; the second is spiritual freedom in his desires, the third is the feeling of inward union with God. 78
Now let every one who thinks himself to be ghostly observe himself. He who would have a heart void of images may not possess anything with affection, nor may he cling to any one, or have intercourse with him with attachment of the will; for all intercourse and all affection which do not aim purely at the honour of God bring images into a man's heart, since they are born, not of God, but of the flesh. And so if a man would become spiritual, he must forsake all fleshly lusts and loves and must cleave with longing and love to God alone, and thus possess Him. And through this, all imaginations and all inordinate love towards creatures are cast out. And this loving possession of God makes a man inwardly free from ungodly images; for God is a Spirit, of Whom no one can make to himself a true image. Certainly in this exercise a man should lay hold of good images to help him; such as the Passion of our Lord and all those things that may stir him to greater devotion. But in the possession of God, the man must sink down to that imageless Nudity which is God; and this is the first condition, and the foundation, of a ghostly life.
The second condition is inward freedom. Through this, the man should be able to raise himself towards God in all inward exercises, free from images and encumbrances; that is, in thanksgiving and praise, in worship, in devout prayer and fervent love, and in all those things that may be done by longing and love with the help of the grace of God and through inward zeal in all ghostly exercises.
Through this inward exercise, he reaches the third state; which is that he feels a ghostly union with God. Whosoever then has, in his inward exercise, an imageless and free ascent unto his God, and means nought else but the glory of God, must taste of the goodness of God; and he must feel from within a true union with God. And in this union, the inward and spiritual life is made perfect; for in this union, the desirous power is perpetually enticed anew and stirred to new inward activity. And by each act, the spirit rises upwards to a new union. And so activity and union perpetually renew themselves; and this perpetual renewal in activity and in union is a ghostly life. And so you are now able to see how a man becomes good through the moral virtues and an upright intention; and how he may become ghostly through the inward virtues and union with God. But without these said points, he can neither be good nor ghostly.