Nicene and Post-Nicene Fathers, Ser. II, Vol. XI:
The Works of John Cassian.: Chapter X. How it is the perfection of love to pray for one's enemies and by what signs we may recognize a mind that is not yet purified.

Chapter X.

How it is the perfection of love to pray for one’s enemies and by what signs we may recognize a mind that is not yet purified.

When then any one has acquired this love of goodness of which we have been speaking, and the imitation of God, then he will be endowed with the Lord’s heart of compassion, and will pray also for his persecutors, saying in like manner: “Father, forgive them, for they know not what they do.” 1712 But it is a clear sign of a soul that is not yet thoroughly purged from the dregs of sin, not to sorrow with a feeling of pity at the offences of others, but to keep to the rigid censure of the judge: for how will he be able to obtain perfection of heart, who is without that by which, as the Apostle has pointed out, the full requirements of the law can be fulfilled, saying: “Bear one another’s burdens and so fulfil the law of Christ,” 1713 and who has not that virtue of love, which “is not grieved, is not puffed up, thinketh no evil,” which “endureth all things, beareth all things.” 1714 For “a righteous man pitieth the life of his beasts: but the heart of the ungodly is without pity.” 1715 And so a monk is quite certain to fall into the same sins which he condemns in another with merciless and inhuman severity, for “a stern king will fall into misfortunes,” and “one who stops his ears so as not to hear the weak, shall himself cry, and there shall be none to hear him.” 1716

Footnotes

S. Luke xxiii. 34.

Gal. vi. 2.

1 Cor. xiii. 4-7.

Prov. xii. 10 (LXX.).

Prov. 13:17, Prov. 21:13.