It is difficult, my brethren, to dispute with an atheist; it is difficult to converse with a stupid man; it is difficult to change an embittered man. It is only with the greatest difficulty that you will convince an atheist, a stupid man or an embittered man with words. Firstly, you must sway them by your deeds. They will come, “by your good works, which they shall behold, to glorify God” (I Pet. 2:12). Do good to him who would quarrel with you, and you will win the argument. A single act of compassion will penetrate to a stupid man and soften a bitter man more quickly than hours of discussion. If atheism and stupidity and bitterness proceed from ignorance, that ignorance is like a fury that is most easily bridled by the influence of good deeds. If you argue with an atheist on his own diabolical terms, you simply strengthen the demon of atheism. If you converse with a stupid man in a spirit of derision, the darkness of stupidity will be made the greater. If you think to change a bitter man by anger, you will merely add more fuel to the fire of bitterness. But a meek and well-intentioned act is like throwing water on the flames.
Always remember the holy apostles and their behavior towards men. If an atheist challenges you, then it is not the man that challenges you but the devil, for man is by nature devout and tends Godwards. If a stupid man scoffs at you, then it is not the man who scoffs but the devil, for man is by nature intelligent. If a bitter man persecutes you, it is not the man that is doing this but the devil, for man is by nature good and well-disposed. It is the devil that challenges us in lengthy debates and fruitless discussions, but he flees from the power of good deeds. Do good in the name of Christ, and the devil will flee. You will be working with men, men who are devout and intelligent and good. Everything, therefore, that you do, be sure that you do it in the name of Christ.
The Prologue from Ochrid: Lives of the Saints and Homilies for Every Day in the Year by Bishop Nikolai Velimirovic from the entry for June 30 (vol. 2, p 380)