The Imitation of Christ, by Thomas a Kempis, tr. by William Benham [1886], at sacred-texts.com
"My Son, take it not sadly to heart, if any think ill of thee, and say of thee what thou art unwilling to hear. Thou oughtest to think worse of thyself, and to believe no man weaker than thyself. If thou walkest inwardly, thou wilt not weigh flying words above their value. It is no small prudence to keep silence in an evil time and to turn inwardly unto Me, and not to be troubled by human judgment.
2. "Let not thy peace depend upon the word of men; for whether they judge well or ill of thee, thou art not therefore any other man than thyself. Where is true peace or true glory? Is it not in Me? And he who seeketh not to please men, nor feareth to displease, shall enjoy abundant peace. From inordinate love and vain fear ariseth all disquietude of heart, and all distraction of the senses."