Know and be assured, that all those thoughts which give disquiet and agitation of mind, are not in any wise from God, who is the Prince of Peace; but they always proceed either from the devil, or from self-love, or from the esteem which we have of ourselves. These are the three fountains from which all our perturbation springs. Therefore, when thoughts of such a nature come to us, we ought to reject them at once, and make no account of them. -St. Francis de Sales
We read of this Saint that he enjoyed an imperturbable peace of heart. He said himself, one day: “What is there that can possibly disturb our peace? If all the world were in confusion, I should not be troubled; for what is all the world worth in comparison with peace of heart?”
When the Abbot Isaac was asked by another monk, why the devils feared him so much, he replied: “At the time I entered religion, I made a resolution never to let an impatient act or angry word escape me, and, by the grace of God, I have never broken it.”
Text from A Year With the Saints (New York: P.J. Kenedy & Sons, 1891).