There are three things that impel us towards what is holy: natural instincts, angelic powers and probity of intention. Natural instincts impel us when, for example, we do to others what we would wish them to do to us (cf. Luke 6:31), or when we see someone suffering deprivation or in need and naturally feel compassion. Angelic powers impel us when, being ourselves impelled to something worthwhile, we find we are providentially helped and guided. We are impelled by probity of intention when, discriminating between good and evil, we choose the good.
St. Maximos the Confessor
Second Century on Love no. 32, Philokalia Vol. 2 edited by Palmer, Sherrard and Ware; Faber and Faber pg. 71, 7th century
Every work which does not have love as its beginning and root is nothing.
St. John Chrysostom
Unknown, 4th century
'But I say to you,' the Lord says, 'love your enemies; do good to those who hate you, pray for those who persecute you.' Why did he command these things? So that he might free you from hatred, sadness, anger and grudges, and might grant you the greatest possession of all, perfect love, which is impossible to possess except by the one you loves all equally in imitation of God.
St. Maximos the Confessor
Unknown, 7th century
Christians should strive in all things and ought not to pass judgment of any kind on anyone, not on the prostitute nor on sinners nor on disorderly persons. But they should look upon all persons with a single mind and a pure eye so that it may be for such a person almost a natural and fixed attitude never to despise or judge or abhor anyone or to divide people and put them into boxes for this is purity of heart, that, when you see the sinner and the weak, you have compassion and show mercy to them.
St. Makarios the Great
Homilies 5.8, 4th century
Why do we judge our neighbors? Because we shun knowing ourselves. Someone busy trying to understand himself has no time to notice the shortcomings of others. Judge yourself ... and you will stop judging others. Judge a poor deed, but do not judge the doer. It is necessary to consider yourself the most sinful of all, and to forgive your neighbor every poor deed.
St. Seraphim of Sarov
Unknown, 19th century
The sign that thou lovest God, is this, that thou lovest thy fellow; and if thou hatest thy fellow, thy hatred is towards God. For it is blasphemy if thou prayest before God while thou art wroth. For thy heart also convicts thee, that in vain thou multipliest words: thy conscience rightly judges that in thy prayers thou profitest nought.
St. Ephraim the Syrian
ON ADMONITION AND REPENTANCE.