The Cloud of Unknowing, ed. by Evelyn Underhill, , at sacred-texts.com
Who should work in the gracious work of this book.
FIRST and foremost, I will tell thee who should work in this work, and when, and by what means: and what discretion thou shalt have in it. If thou asketh me who shall work thus, I answer thee—all that have forsaken the world in a true will, and thereto that give them not to active life, but to that life that is called contemplative life. All those should work in this grace and in this work, whatsoever that they be; whether they have been accustomed sinners or none. p. 167