Faith and contrition make prayer and supplication for the remission of sins effective, once evil deeds have been renounced, but despair and hardness of heart make it ineffectual. Thanksgiving for the benefits received from God is made acceptable by humility and not looking down on those who lack them. it is rendered unacceptable, however, by being conceited, as if those benefits resulted from our own efforts and knowledge, and by condemning those who have not received them. the Pharisee’s behaviour and words prove he was afflicted with both these diseases. He went up to the Temple to give thanks, not to make supplication and, like a wretched fool, mingled conceit and condemnation of others with his thanksgiving. For he stood and prayed thus with himself: “God, I thank thee, that I am not as other men are, extortioners, unjust, adulterers” (Luke 18:11).
+ St. Gregory Palamas, The Parables of Jesus, Sermons by St. Gregory Palamas