The Adornment of the Spiritual Marriage, by Jan van Ruysbroeck, , at sacred-texts.com
Further, you must know that if this ghostly man would now become a God-seeing man, he needs must have three other things. The first is the feeling that the foundation of his being is abysmal, and he should possess it in this manner; the second is that his inward exercise should be wayless; the third is that his indwelling should be a divine fruition.
Now understand, you who would live in the spirit, for I am speaking to no one else. The union with God which a spiritual man feels, when the union is revealed to the spirit as being abysmal—that is, measureless depth, measureless height, measureless length and measureless breadth—in this manifestation the spirit perceives that through love it has plunged itself into the depth and has ascended into the height and escaped into the length; and it feels itself to be wandering in the breadth, and to dwell in a knowledge which is ignorance. And through this intimate feeling of union, it feels itself to be melting into the Unity; and, through dying to all things, into the life of God. And there it feels itself to be one life with God. And this is the foundation, and the first point, of the God-seeing life.
And from this there arises the second point, which is an exercise above reason and without condition: for the Divine Unity, of which every God-seeing spirit has entered into possession in love, eternally draws and invites the Divine Persons and all loving spirits into its self. And this inward drawing is felt by each lover, more or less, according to the measure of his love and the manner of his exercise. And whosoever yields himself to this indrawing, and keeps himself therein, cannot fall into mortal sin. But the God-seeing man who has forsaken self and all things, and does not feel himself drawn away because he no longer possesses anything as his own, but stands empty of all, he can always enter, naked and unencumbered with images, into the inmost part of his spirit. There he finds revealed an Eternal Light, and in this light, he feels the eternal demand of the Divine Unity; and he feels himself to be an eternal fire of love, which craves above all else to be one with God. The more he yields to this indrawing or demand, the more he feels it. And the more he feels it, the more he craves to be one with God; for it urges him to pay the debt which is demanded of him by God. This eternal demand of the Divine Unity kindles within the spirit an eternal fire of love; and though the spirit incessantly pays the debt, an eternal burning continues within it. For, in the transformation within the Unity, all spirits fail in their own activity, and feel nothing else but a burning up of themselves in the simple Unity of God. This simple Unity of God none can feel or possess save he who maintains himself in the immeasurable radiance, and in the love which is above reason and wayless. In this transcendent state the spirit feels in itself the eternal fire of love; and in this fire of love it finds neither beginning nor end, and it feels itself one with this fire of love. The spirit for ever continues to burn in itself, for its love is eternal; and it feels itself ever more and more to be burnt up in love, for it is drawn and transformed into the Unity of God, where the spirit burns in love. If it observes itself, it finds a distinction and an otherness between itself and God; but where it is burnt up it is undifferentiated and without distinction, and therefore it feels nothing but unity; for the flame of the Love of God consumes and devours all that it can enfold in its Self.
And thus you may see that the indrawing Unity of God is nought else than the fathomless Love, which lovingly draws inward, in eternal fruition, the Father and the Son and all that lives in Them. And in this Love we shall burn and be burnt up without end, throughout eternity; for herein lies the blessedness of all spirits. And therefore we must all found our lives upon a fathomless abyss; that we may eternally plunge into Love, and sink down in the fathomless Depth. And with that same Love, we shall ascend, and transcend ourselves, in the incomprehensible Height. And in that Love which is wayless, we shall wander and stray, and it shall lead us and lose us in the immeasurable Breadth of the Love of God. And herein we shall flee forth and flee out of ourselves, into the unknown raptures of the Goodness and Riches of God. And therein we shall melt and be melted away, and shall eternally wander and sojourn within the Glory of God. Behold! by each of these images, I show forth to God-seeing men their being and their exercise, but none else can understand them. For the contemplative life cannot be taught. But where the Eternal Truth reveals Itself within the spirit all that is needful is taught and learnt.