"...abstaining from sinful actions and fear of suffering are not sufficient for spiritual life... only the guarding of the mind and purity of heart will free one's soul from sinful thoughts ... inner freedom can be obtained only through interior prayer and ... not through fear of the sufferings of hell or even the desire for the bliss of heaven. The holy Fathers consider even heroic deeds as the act of a hireling. They claim that the fear of suffering is the way of a slave and that desire for a reward is the way of a hireling. But God wants us to come to Him on a path of a son; motivated by love and zeal for His glory, we should conduct ourselves with honor and enjoy His saving presence in our hearts and souls."
-- from The Way of a Pilgrim