Commentary on Luke by Cyril of Alexandria | Sermon 29
The Lord said, “And as you wish that men would do to you, do so to them” (Luke 6:31)
It was probable however that the holy apostles would perchance think these things difficult to put into practice: He therefore Who knoweth all things takes the natural law of self-love as the arbiter of what any one would wish to obtain from another. Shew thyself, He says, to others such as thou wishest them to be towards thee. If thou wouldest have them harsh and unfeeling, fierce and wrathful, revengeful and ill-disposed, shew thyself also such: but if on the contrary thou wouldst have them kind and forgiving, do not think it a thing intolerable to be thyself so. And in the case of those so disposed, the law is perchance unnecessary, because God writes upon our hearts the knowledge of His will: "for in those days, saith the Lord, I will surely give My laws into their mind, and will write them on their heart."
The Lord said, “Be merciful, even as your Father is merciful.” (Luke 6:31)
Great is the glory of compassion, and so verily it is written, that "man is a great thing, and the merciful man an honourable thing." For virtue restores us to the form of God, and imprints on our souls certain characters as it were of the supreme nature.