Chapter XXII. That we should for this reason practise bodily abstinence that we may by it attain to a spiritual fast. And so we know that we ought therefore to bestow attention on bodily abstinence, that we may by this fasting attain to purity of heart. Otherwise our labours will be spent in vain, if we endure this without weariness, in contemplating the end, but are unable to reach the end for which we have endured such trials; and it would have been better to have abstained from the forbidden foods of the soul than to have fasted with the body from things indifferent and harmless, for in the case of these latter there is a simple and harmless reception of a creature of God, which in itself has nothing wrong about it: but in the case of the former there is at the very first a dangerous tendency to devour the brethren; of which it is said, “Do not love backbiting lest thou be rooted out.” 862 And concerning anger and jealousy the blessed Job says: “For anger slayeth a fool, and envy killeth a child.” 863 And at the same time it should be noticed that he who is angered is set down as a fool; and he who is jealous, as a child. For the former is not undeservedly considered a fool, since of his own accord he brings death upon himself, being goaded by the stings of anger; and the latter, while he is envious, proves that he is a child and a minor, for while he envies another he shows that the one at whose prosperity he is vexed, is greater than he. 862     Prov. xx. 13 . (LXX.). 863     Job v. 2 .