Entry 0178: In his reflections on prayer in the General Audience of 11 May 2011, Pope Benedict XVI refers to Saint Thomas Aquinas as follows:
Man bears within him a thirst for the infinite, a longing for eternity, a quest for beauty, a desire for love, a need for light and for truth which impel him towards the Absolute; man bears within him the desire for God. And man knows, in a certain way, that he can turn to God, he knows he can pray to him.
St Thomas Aquinas, one of the greatest theologians of history, defines prayer as “an expression of man’s desire for God”. This attraction to God, which God himself has placed in man, is the soul of prayer, that then takes on a great many forms, in accordance with the history, the time, the moment, the grace and even the sin of every person praying.
Indeed in the Summa Theologiae (part II-II, question 83, article 9, corpus) Aquinas writes: "For since prayer interprets our desires, as it were, before God, then alone is it right to ask for something in our prayers when it is right that we should desire it." (Oratio est quodammodo desiderii nostri interpres apud Deum, illa solum recte orando petimus quae recte desiderare valemus.)