Archbishop Leighton, for instance, speaks of the Christian, who perceives himself "knit to God, and his soul more fast and joined nearer to him than to his own body."
John Climacus, many centuries since a devout and learned recluse of Mount Sinai.
"My God, I pretend to nothing upon this earth, except to be so firmly UNITED to Thee by prayer, that to be separated from Thee may be impossible. Let others desire riches and glory; for my part I desire but one thing, and that is to be inseparably UNITED to Thee, and to place in Thee alone all my hopes of happiness and repose."
These expressions indicate a full belief, on the part of this devout person, of the existence of the state of present mental union with God, as well as earnest desire for it. There are repeated allusions to this state of mind in the works of Thomas à Kempis and Tauler; writers, who, although Catholics, are favorably mentioned by Luther; and have always been much esteemed by Protestant Christians.
Sir Henry Vane, one of the English Puritans, a man religiously as well as politically memorable, wrote a religious treatise, which in part had express relation to this subject, entitled, ON THE LOVE OF GOD AND UNION WITH GOD.
Many pious persons in more modern times, and in different denominations of Christians have spoken very emphatically of their union with the Divine Mind; and in such way as to leave the impression, that they considered the state of union as a distinct and peculiar, as well as a very desirable and eminent modification of Christian experience.
"Time would fail me," says Lady Maxwell, "to tell of the numberless manifestations of divine love and power. I have, though deeply unworthy, been favored with such wonderful lettings into Deity, as no language can describe or explain; but the whole soul dilates itself in the exquisite enjoyment; so refined, so pure, so tempered with sacred awe, so guarded by heavenly solemnity, as effectually to prevent all irregularity of desires. These, with every power of the mind, bow in holy subjection before Jehovah. Surely the feelings of the soul, on these memorable occasions, are nearly similar to those enjoyed by the heavenly inhabitants. I have it still to remark, that all my intercourse with God the Father is strongly marked with that superior solemnity and awe which lay and keep the soul in the dust, yet raised to that holy dignity, which flows from a consciousness of union with the Deity."
— edited from The Interior or Hidden Life (2nd edition, 1844) Part 3, Chapter 13.