If I give all my goods to feed the poor... if I add to this sacrifice the fiery martyrdom of my flesh; if I hand my body over for the sake of Christ; if, nevertheless, I am impatient, prone to anger, jealous, proud; if I become enraged when wrongs are done to me; if I am on the lookout for my own interest; if my thoughts are evil; if I do not patiently and gladly endure all that happens to me; then the renunciation and the martyrdom of the outer man will be of no benefit to me as long as the inner spirit wallows in its old and sinful ways. It will be of no value that when in the first zeal of conversion I despised the simple substance of the world, which is neither good nor bad but neutral, if I took no care to throw out at the same time the evil goods of a corrupt heart and made no effort to achieve a Godlike love, a love which is patient and kind, which is not jealous, not boastful, which does not show annoyance or is wrong-headed, which is not on the lookout for itself, which thinks no evil, which endures all and sustains all, and which, finally, never allows itself to slip into the snares of sin.
- St. John Cassian