5 The remedies for propitiating God are given in the words of God Himself; the divine instructions have taught what sinners ought to do, that by works of righteousness God is satisfied, that with the deserts of mercy sins are cleansed. And in Solomon we read, “Shut up alms in the heart of the poor, and these shall intercede for you from all evil.” And again: “Whoever stops his ears that he may not hear the weak, he also shall call upon God, and there will be none to hear him.” For he shall not be able to deserve the mercy of the Lord, who himself shall not have been merciful; nor shall he obtain anything from the divine pity in his prayers, who shall not have been humane towards the poor man's prayer.
And this also the Holy Spirit declares in the Psalms, and proves, saying, Blessed is he that considers of the poor and needy; the Lord will deliver him in the evil day. Remembering which precepts, Daniel, when king Nebuchodonosor was in anxiety, being frightened by an adverse dream, gave him, for the turning away of evils, a remedy to obtain the divine help, saying, “Wherefore, O king, let my counsel be acceptable to you; and redeem your sins by almsgivings, and your unrighteousness by mercies to the poor, and God will be patient to your sins.” And as the king did not obey him, he underwent the misfortunes and mischiefs which he had seen, and which he might have escaped and avoided had he redeemed his sins by almsgiving.
Raphael the angel also witnesses the like, and exhorts that alms should be freely and liberally bestowed, saying, “Prayer is good, with fasting and alms; because alms does deliver from death, and it purges away sins.” He shows that our prayers and fastings are of less avail, unless they are aided by almsgiving; that entreaties alone are of little force to obtain what they seek, unless they be made sufficient by the addition of deeds and good works. The angel reveals, and manifests, and certifies that our petitions become efficacious by almsgiving, that life is redeemed from dangers by almsgiving, that souls are delivered from death by almsgiving.
Source: The Treatises of Cyprian (New Advent)