We need to regard all the faithful as one and think that each one of them is Christ. We need to have such love for each individual that we are ready to sacrifice our very life for him. Because we ought never to say or think that any person is evil, but rather to regard all as good. And if you see a brother troubled by passions, do not hate him. Hate rather the passions that are assailing him. And if you see that he is being tormented by desires and habits from former sins, have even greater compassion on him, lest you also fall into temptation, since you are made of matter that easily turns from good to evil. Love for your brother prepares you to love God more. Accordingly, the secret of love for God is love for your brother. Because if you don’t love your brother whom you see, how can you possible love God whom you don’t see?
“He who does not love his brother whom he has seen, how can he love God whom he has not see?” (1 John 4:20) Words of Saint Symeon the New Theologian interspersed with Elder Porphyrios’s own words from One Hundred Theological and Practical Chapters, of Saint Symeon.
Reference: Wounded By Love, p 183 - 184