The Cloud of Unknowing, ed. by Evelyn Underhill, [1922], at sacred-texts.com
Of three means in the which a contemplative Prentice should be occupied, in reading, thinking, and praying.
NEVERTHELESS, means there be in the which a contemplative prentice should be occupied, the which be these—Lesson, Meditation, and Orison: or else to thine understanding they may be called—Reading, Thinking, and Praying. Of these three thou shalt find written in another book of another man’s work, much better than I can tell thee; and therefore it needeth not here to tell thee of the qualities of them. But this may I tell thee: these three be so coupled together, that unto them that be beginners and profiters—but not to them that be p. 186 perfect, yea, as it may be here—thinking may not goodly be gotten, without reading or hearing coming before. All is one in manner, reading and hearing: clerks reading on books, and lewd men reading on clerks when they hear them preach the word of God. Nor prayer may not goodly be gotten in beginners and profiters, without thinking coming before.
See by the proof. In this same course, God’s word either written or spoken is likened to a mirror. Ghostly, the eyes of thy soul is thy reason; thy conscience is thy visage ghostly. And right as thou seest that if a foul spot be in thy bodily visage, the eyes of the same visage may not see that spot nor wit where it is, without a mirror or a teaching of another than itself; right so it is ghostly, without reading or hearing of God’s word it is impossible to man’s understanding that a soul that is blinded in custom of sin should see the foul spot in his conscience. p. 187
And so following, when a man seeth in a bodily or ghostly mirror, or wots by other men’s teaching, whereabouts the foul spot is on his visage, either bodily or ghostly; then at first, and not before, he runneth to the well to wash him. If this spot be any special sin, then is this well Holy Church, and this water confession, with the circumstances. If it be but a blind root and a stirring of sin, then is this well merciful God, and this water prayer, with the circumstances. And thus mayest thou see that no thinking may goodly be gotten in beginners and profiters, without reading or hearing coming before: nor praying without thinking. p. 188