"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."

Blessed Jan van Ruysbroeck – ‘THE BOOK OF SUPREME TRUTH’ – Chapters XIII; ‘OF THE THREEFOLD PRAYER OF CHRIST…’; pages 127-128
[BLESSED JAN VAN RUYSBROEK – XIII-XIV Century AD; born: Ruisbroek, Holy Roman Empire/ died: Groenendael, Holy Roman Empire; aged 87-88, Mystic, Spiritual Writer, Doctor Divinus Ecstaticus]
Chapter XIII ~ OF THE THREEFOLD PRAYER OF CHRIST, THAT WE MIGHT BE ONE WITH GOD
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 …More