This thought is naturally connected with contempt of the world. And then begin all the beautiful emotions which educate unto life.
That divine power which accompanies man makes as it were a foundation in him, which desires to reveal life in him.
As to this emotion which I mentioned, if a man does not extinguish it by clinging to the things of this world and to idle intercourse, and if he makes this emotion increase in his soul by perpetual concentration and by gazing at himself, he will bring himself near to that which no tongue is able to tell.
This thought is greatly hated by Satan and he strives with all his power to eradicate it from man.
And if he were able to give him the kingdom of the whole earth in order to efface by thought of it from his mind this deliberation, he would not do otherwise.
For Satan knows that if this recollection remains with him, his mind will no longer stay in this world of error, and his means will not reach man.
This sight is clad with fiery emotions and he that has caught it will no longer contemplate the world nor remain with the body.
Verily, my beloved, if God should grant this veracious sight unto the children of man for a short time, the course of the world would stand still.
It is a bond before which nature cannot stand upright. And he unto whim this intercourse with his soul is given — verily, it is a gift from God, stronger than all partial workings, which in this middle state are presented unto those who with an upright heart desire repentance.
It is especially given to him of whom God knows that he is worthy of the real transition from this world unto profitable life, because He finds good will in him.
It will increase and remain with a man through his dwelling alone by himself. Let us ask this gift in prayer; and for the sake of this gift let us make long vigils.
And as it is a gift without equal, let us keep watch with tears at the gate of our Lord, that He may give it us. Further we need not weary ourselves with the trouble of this world.
This is the beginning of the impulse of life, which will fully bring about in a man the perfection of righteousness.
Isaac the Syrian (c. 630-c. 700): Mystic Treatises, 47, in Mystical Treatises of Isaac of Nineveh, trans. A.J. Wensinck, pp.225-226.