Didascalicon, Book III: the art of study (discipline and method)
Chapter XIII. On discipline
A wise man, when asked about the manner and form of learning, answered: “A humble mind, zeal for inquiry, a quiet life, silent scrutiny, poverty, a foreign land: these are wont to unlock some obscure things for the reader.” He had heard, I think, what was said: “Morals adorn knowledge,” and therefore to the precepts of reading he adds precepts also, that the reader may know the manner of his life and the method of his study. Knowledge is not laudable which an unchaste life stains. And therefore he who seeks knowledge must above all take care not to neglect discipline.