On the Lord's Prayer 32

And let those who pray not come to God with fruitless or bare prayers. A petition is ineffective when a barren prayer entreats God. For since every tree that does not bear fruit is cut down and thrown into the fire, surely words that bear no fruit cannot win God's favour either, because they are fruitful in no good work. And therefore the divine Scripture instructs us, saying: "Prayer is good with fasting and almsgiving." For he who on the day of judgment will render a reward for works and alms is today too a kind hearer of one who comes to prayer with good works. So, finally, Cornelius the centurion, when he prayed, deserved to be heard. He was one who did many alms among the people and always prayed to God. As he was praying about the ninth hour, an angel stood by him, bearing witness to his deeds and saying: "Cornelius, your prayers and your alms have gone up for a remembrance before God."