[A]dvocates of autonomous morality attack Christian morality as if it were motivated by primitive moral principles: fear of future torments in hell and the desire for a reward in the future life. The Gospel indeed speaks of rewards that await the righteous and punishments that will befall unrepentant sinners. However, nowhere are these rewards and punishments offered as the main, exclusive motivation for a Christian. In fact, these rewards and punishments are not the motivation but the natural end result of one’s lifestyle. Christ explains that the narrow and sorrowful path of life preached by Him has as its natural end eternal joy, while the broad and easy path, counter to the Gospel, culminates in eternal grief, eternal torment. These are not incentives, not external pedagogical methods to force a person to act in a certain way. They are the natural results of a chosen lifestyle, which He warns against and makes abundantly clear. It is long overdo for us to reject that absurd and even blasphemous notion that floated over to us from Catholicism that God rewards us for good deeds and punishes us for evil ones. God does not want anyone to perish but desires all people to be saved and come to knowledge of the truth. A person destroys himself, since evil deeds frequently repeated make a person evil in his nature and incapable of experiencing that light and joy, which is the natural lot of those who are good. The only motive of Christian morality is love, love for God as our Father and Benefactor. St John the Apostle and Evangelist says, We love Him because He first loved us. (1 John 4:19). And He Himself is the propitiation for our sins, and not for ours only but also for the whole world (1 John 2:2). Beloved, if God so loved us, we also ought to love one another (1 John 4:10–11). If someone says, “I love God,” and hates his brother, he is a liar: for he who does not love his brother whom he has seen, how can he love God whom he has not seen (1 John 4:20)? And this commandment have we from Him: That he who loves God must love his brother also (1 John 4:21). How is our love expressed for God and what is the proof of its sincerity? The Apostle explains: For this is the love of God, that we keep His commandments. And His commandments are not burdensome (1 John 5:3).
What could possibly be greater than such motivation? On the other hand, what kind of real incentive does autonomous morality offer us? “Good for goodness’ sake”? Such an idea is very obscure. (The Struggle for Virtue: Asceticism in a Modern Secular Society [kindle version])