Thomas a Kempis, The Imitation of Christ 3.43

Against vain and worldly knowledge

1. "My Son, let not the fair and subtle sayings of men move you. For the kingdom of God is not in word, but in power. Give ear to My words, for they kindle the heart and enlighten the mind, they bring contrition, and they supply manifold consolations. Never read you the word that you may appear more learned or wise; but study for the mortification of your sins, for this will be far more profitable for you than the knowledge of many difficult questions. 

2. "When you have read and learned many things, you must always return to one first principle. I am He that teaches man knowledge, and I give unto babes clearer knowledge than can be taught by man. He to whom I speak will be quickly wise and shall grow much in the spirit. Woe unto them who inquire into many curious questions from men, and take little heed concerning the way of My service. The time will come when Christ will appear, the Master of masters, the Lord of the Angels, to hear the lessons of all, that is to examine the consciences of each one. And then will He search Jerusalem with candles, and the hidden things of darkness shall be made manifest, and the arguings of tongues shall be silent.

3. "I am He who in an instant lifts up the humble spirit, to learn more reasonings of the Eternal Truth, than if a man had studied ten years in the schools. I teach without noise of words, without confusion of opinions, without striving after honor, without clash of arguments. I am He who teach men to despise earthly things, to loathe things present, to seek things heavenly, to enjoy things eternal, to flee honors, to endure offenses, to place all hope in Me, to desire nothing apart from Me, and above all things to love Me ardently.

4. "For there was one, who by loving Me from the bottom of his heart, learned divine things, and spoke things that were wonderful; he profited more by forsaking all things than by studying subtleties. But to some I speak common things, to others special; to some I appear gently in signs and figures, and again to some I reveal mysteries in much light. The voice of books is one, but it informs not all alike; because I inwardly am the Teacher of truth, the Searcher of the heart, the Discerner of the thoughts, the Mover of actions, distributing to each man, as I judge meet."