33 Those prayers quickly ascend to God which the merits of our labours urge upon God. Thus also Raphael the angel was a witness to the constant prayer and the constant good works of Tobias, saying, “It is honourable to reveal and confess the works of God. For when you prayed, and Sarah, I did bring the remembrance of your prayers before the holiness of God. And when you buried the dead in simplicity, and because you did not delay to rise up and to leave your dinner, but went out and covered the dead, I was sent to prove you; and again God has sent me to heal you, and Sarah your daughter-in-law.
For I am Raphael, one of the seven holy angels which stand and go in and out before the glory of God.” By Isaiah also the Lord reminds us, and teaches similar things, saying, “Loosen every knot of iniquity, release the oppressions of contracts which have no power, let the troubled go into peace, and break every unjust engagement. Break your bread to the hungry, and bring the poor that are without shelter into your house. When you see the naked, clothe him; and despise not those of the same family and race as yourself.
Then shall your light break forth in season, and your raiment shall spring forth speedily; and righteousness shall go before you, and the glory of God shall surround you. Then shall you call, and God shall hear you; and while you shall yet speak, He shall say, Here I am.” He promises that He will be at hand, and says that He will hear and protect those who, loosening the knots of unrighteousness from their heart, and giving alms among the members of God's household according to His commands, even in hearing what God commands to be done, do themselves also deserve to be heard by God.
The blessed Apostle Paul, when aided in the necessity of affliction by his brethren, said that good works which are performed are sacrifices to God. “I am full,” says he. “having received of Epaphroditus the things which were sent from you, an odour of a sweet smell, a sacrifice acceptable, well pleasing to God.” For when one has pity on the poor, he lends to God; and he who gives to the least gives to God— sacrifices spiritually to God an odour of a sweet smell.
Source: The Treatises of Cyprian (New Advent)