Thomas a' Kempis
“Never promise yourself security in this life, even though you seem to be a good religious, or a devout hermit. It happens very often that those whom men esteem highly are more seriously endangered by their own excessive confidence. Hence, for many it is better not to be too free from temptations, but often to be tried lest they become too secure, too filled with pride, or even too eager to fall back upon external comforts. If only a man would never seek passing joys or entangle himself with worldly affairs, what a good conscious he would have. What great peace and tranquility would be his, if he cut himself off from all empty care and thought only of things divine, things helpful to his soul, and put all his trust in God.“
Source: Thomas a’ Kempis, The Imitation of Christ, Dover Thrift Editions, 1940.