The Adornment of the Spiritual Marriage, by Jan van Ruysbroeck, , at sacred-texts.com
But you should also observe that His prayer, as it has been written by St John in this same Gospel, was threefold. For He prayed that we might be with Him, that we might behold the glory which His Father had given Him. And therefore I said at the beginning that all good men are united with God by means of Divine grace and their own virtuous life; for the love of God is always pouring into us with new gifts, and whosoever is aware of this is fulfilled with new virtues and holy exercises and with all good, in the way that I told you heretofore: and this union through the fulness of grace and glory, in body and soul, begins here below and shall endure throughout eternity.
Further, Christ prayed thus, that He might be in us and we in Him. This we find in the Gospel, in many places. And this is the union without means; for the Love of God is not only outpouring, but it also draws us inwards, into the Unity. And those who feel and are aware of this, become inward and enlightened men, and their highest powers are uplifted, above all exercises, into their naked being: and there, above reason, the powers become simplified in their essence, and so they are full and overflowing. For in that simplicity, the spirit finds itself united with God without means; and this union, with the exercise which belongs to it, shall endure eternally, as I have told you heretofore.
Further, Christ uttered His most sublime prayer, namely, that His beloved might be made perfect in one, as He is one with the Father: not one as He is with the Father one single Divine Substance, for this is impossible to us; but so one, and in such a unity, as He is one fruition and one beatitude with the Father without distinction in Essential Love. Those who are thus united with God in this threefold way, in them the prayer of Christ has been fulfilled.
These with God shall ebb and flow,
Having and joying, they shall empty go;
They shall both work and passively endure,
And in their superessence rest secure.
They shall go out and in, and find their food,
And, drunk with love, in radiant darkness sleep in God.
Many more words I should like to say here, but those who possess this have no need of them: and he to whom it has been shown, and who cleaves with love to Love, he shall be taught the whole truth by Love itself. But those who turn outwards, and would find consolation in outward things, do not feel this; and, even though I should say much more of it, yet they would not understand. For those who give themselves wholly to outward works, or those who are idle in inward passivity, shall never be able to understand it. Now although reason and all bodily feelings must here give place and yield to the faith and contemplation of the spirit, 89 and to those things which are above reason; yet reason and also the life of the senses continue to abide in their place, and cannot pass away, any more than the nature of man can pass away. And further, though the gazing and tendency of the spirit towards God must give place to fruition in simplicity; yet this gazing and this tendency continue to exist in their place. 90 For this is the inmost life of the spirit; and, in the enlightened and uplifted man, the life of the senses adheres to the spirit. And so his sensual powers are joined to God by heart-felt love, and his nature is fulfilled with all good; and he feels that his ghostly life adheres to God without means. And thereby his highest powers are uplifted to God in eternal love, and drenched through by Divine truth, and established in imageless freedom. And so he is filled with God, and overflowing without measure. In this inundation there comes to pass the essential outpouring or immersion in the superessential Unity; and this is the union without distinction, of which I have often told you. For in the superessence all our ways end. If we will go with God upon the highway of love, we shall rest with Him eternally and without end: and thus we shall eternally go forth towards God and enter into Him and rest in Him.