THE CLOUD OF UNKNOWING, CHAPTER 67
That whoso knoweth not the powers of a soul and the manner of her working, may lightly be deceived in understanding of ghostly words and of ghostly working; and how a soul is made a God in grace.
A paragraph of this chapter could serve as a good summary of what we're about in the practice of the exercise described in The Cloud of Unknowing:
For ever when the Memory is occupied with any bodily thing be it taken to never so good an end, yet thou art beneath thyself in this working, and without any soul. And ever when thou feelest thy Memory occupied with the subtle conditions of the powers of thy soul and their workings in ghostly things, as be vices or virtues, of thyself, or of any creature that is ghostly and even with thee in nature, to that end that thou mightest by this work learn to know thyself in furthering of perfection: then thou art within thyself, and even with thyself. But ever when thou feelest thy Memory occupied with no manner of thing that is bodily or ghostly, but only with the self substance of God, as it is and may be, in the proof of the work of this book: then thou art above thyself and beneath thy God.