Ps 50:1

“Beloved, let us praise her, through whom we have been saved. Let us love her; let us prefer her to wealth. Let us have a merciful soul apart from wealth. Nothing is more characteristic of a Christian than mercy. There is nothing that unbelievers and all people are so amazed at as when we are merciful. For we ourselves are often in need of this mercy and say to God, "Have mercy on us according to the greatness of your mercy." Let us begin first ourselves; yet we do not begin first. For he has already shown his mercy that he has toward us. But, beloved, let us follow second. For if people have mercy on one who was merciful, even if he has committed countless sins, God is much more merciful.”

“Psalm 50 [51] shows the complete repentance of a sinner when David, who had gone into Bathsheba, the wife of Uriah the Hittite and was rebuked by the prophet Nathan, said, "I have sinned." Immediately he deserved to hear "The Lord has removed your sin from you." For he, who had added homicide to adultery and was moved to tears, said, "God, have compassion on me according to your great pity, and according to the multitude of your mercies take away my iniquity." Since a great sin needed great mercy, he added, "Wash me completely from my iniquity, and my offense is always before me. I have sinned against you only"—for a king did not fear anyone else—"and I have done evil in your sight so that you will be justified in your speaking and you overcome when you judge." "For God has included all things under sin so that he may be merciful to all." He made so much progress that he who a little earlier had been a penitent sinner became a master and was able to say, "I will teach the unjust your ways, and sinners will be converted to you." Since confession and beauty are before God, the one who confesses his sins and says, "My wounds have been destroyed and become putrefied," changes the foulness of his wounds into a healthy state. But "he who hides his sins will not prosper."”

“Hear therefore these words, and say thou with him: "Have pity upon me, O God, after Thy great mercy" [Psalm 51:1]. He that imploreth great mercy, confesseth great misery. Let them seek a little mercy of Thee, that have sinned in ignorance: "Have pity," he saith, "upon me, after Thy great mercy." Relieve a deep wound after Thy great healing. Deep is what I have, but in the Almighty I take refuge. Of my own so deadly wound I should despair, unless I could find so great a Physician. "Have pity upon me, O God, after Thy great mercy: and after the multitude of Thy pities, blot out my iniquity." What he saith, "Blot out my iniquity," is this, "Have pity upon me, O God." And what he saith, "After the multitude of Thy pities," is this, "After Thy great mercy." Because great is the mercy, many are the mercies; and of Thy great mercy, many are Thy pitying. Thou dost regard mockers to amend them, dost regard ignorant men to teach them, dost regard men confessing to pardon. Did he this in ignorance? A certain man had done some, aye many evil things he had done; "Mercy," he saith, "I obtained, because ignorant I did it in unbelief." This David could not say, "Ignorant I did it." For he was not ignorant how very evil a thing was the touching of another's wife, and how very evil a thing was the killing of the husband, who knew not of it, and was not even angered. They obtain therefore the mercy of the Lord that have in ignorance done it; and they that have knowing done it, obtain not any mercy it may chance, but "great mercy."”

“Finally, holy David successfully gained divine mercy because, having been converted by the humility of a contrite heart, he condemned the evil he had done by acknowledging it and did not put off punishment by doing penance for the lust of the evil deed he had fallen into; because, if he had not punished the cause of the guilt in which he was held, without a doubt he would have been punished. Having been converted to penance, he acknowledged his crime, fearing lest he would have to acknowledge the penalty by being condemned. By doing penance, he punished himself by acknowledging what he wanted to be overlooked by the Lord in himself. Finally, since he said, "Have mercy on me, O God, according to your steadfast love; according to your abundant mercy blot out my transgressions. Wash me thoroughly from my iniquity, and cleanse me from my sin." Immediately following this he added, "For I know my transgressions, and my sin is ever before me." He acknowledged his sin, not that by sinning he might increase it the more, but that by repenting, he might wash it away; and so the domination of sin, which blameworthy enjoyment had brought in, true conversion removed. And because David, converted with all his heart, groaned, he was immediately saved and thus in him was fulfilled what is commanded through the prophet: "If you are converted and groan, you will be saved."”

“In the preceding Psalms of this decade, the Psalmist seems to have treated of those things that pertain to the state of the kingdom, whose glory he described and to which he invited others. But now, because the glory of this kingdom has been impeded by sin, he treats of the abolition of sin. Here two things must be considered. First, that in the order of the Psalms, this Psalm is the fiftieth, and this is the jubilee number, as is said in Lev. 27, in which the remission of all debts was made. Hence this number is fitting for this Psalm, in which he treats of the full remission of sins. Similarly, as regards the penitential Psalms, this one is placed fourth, and fittingly so: for the first pertains to contrition of heart; hence it says, Ps. 6: "Every night I will wash," etc. The second pertains to confession of mouth, Ps. 31: "I said, I will confess," etc. The third pertains to satisfaction; hence it says, Ps. 37: "I am afflicted," etc. But this fourth pertains to the effect of penance. In it is shown how penance restores a person to perfection; and therefore, among all the others, this Psalm is most frequently used in the Church, because this one solely implores mercy, and thus obtains pardon; and this is easy and can be fitting for anyone. In the other six penitential Psalms, there are certain heavy things, such as Ps. 6: "Every night I will wash my bed." And Ps. 101: "I ate ashes like bread," etc., which cannot be fitting for everyone. The title is as follows: "A Psalm of David, when Nathan the prophet came to him after he had gone in to Bathsheba." This history is expressly found in 2 Sam. 11 and 12, when David was in prosperity, saw a woman washing herself, and desired her, and committed adultery, and had her husband killed. And this displeased God, and Nathan the prophet was sent to him and brought him to the detestation of his sin under the likeness of a lost sheep. And David said, "I have sinned against the Lord." And his sin was forgiven. And this is the subject matter of this Psalm, namely the forgiveness of sin. But it should be known regarding the title of this Psalm that David in other Psalms speaks about others -- as in Ps. 21, "O God, my God," he speaks foretelling the Passion of Christ; and so in various Psalms he speaks about various things -- but this Psalm he composed for his own sake. In it he shows the guilt he committed, made manifest to the world, and similarly the pardon; and thus is fulfilled what the Lord said, 2 Sam. 12: "You did this in secret, and I will make it manifest." The reason for this manifestation is the divine mercy; for this manifestation is useful to the just, so that they may not presume on their own justice, because if David, after so many victories, after the gift of the Holy Spirit, after such great familiarity with God and prophecy, sinned, how much more should we, who are fragile and sinners, be on guard? 1 Cor. 10: "Let him who thinks he stands take heed lest he fall." Also, it is useful to sinners, so that they may not despair. Prov. 24: "If you despair, having fallen, in the day of anguish your strength will be diminished"; for David, after homicide and adultery, recovered the grace of prophecy. The manner of speaking in the title should be noted: "when he came" -- here he designates the pardon, which is treated in the Psalm, because through Nathan the Lord heard him and transferred his sin. But when it says, "when he went in to Bathsheba," the guilt is designated. Here two things are shown. First, that he names the guilt when he says, "and he went in." Ps. 11: "The words of the Lord are chaste words." Also, though he had committed two sins, namely adultery and homicide, Scripture named only the adultery. And this for two reasons. First, to designate that in scrutinizing and publicizing the sins of others, we should not be ready but very sparing. Prov. 24: "Do not lie in wait to seek wickedness in the house of the just"; and this is signified in Mt. 25, where the Lord enumerates the merits of the good diligently but passes over the demerits of the wicked. Also, it should be noted that when someone commits two sins and one is done for the sake of the other, one passes into the species of the other; just as one who commits theft in order to fornicate is called a fornicator rather than a thief. Now this Psalm is divided into two parts. First, he implores mercy; second, he promises amendment, at "I will teach the unjust." Regarding the first, he does two things. First, he asks for the relaxation of guilt; second, he asks for the restoration of holiness and grace, at "because my iniquity." He therefore first asks for the mercy of God, when he says, "Have mercy on me, O God." Here it should be known that, as is said in Prov. 14, "Sin makes peoples wretched." For just as one is not truly happy who abounds in riches, enjoys pleasures, and excels in honors, but rather one who enjoys God, so one is not wretched who is poor, miserable, weak, and infirm, but rather one who is a sinner. And therefore this man, who is a sinner, says, "Have mercy on me, O God," you who have mercy on all and hate nothing of what you have made, Wis. 11. And according to the apostle, "have mercy on whom you will," Rom. 9: "I will have mercy on whom I will." Therefore, if it is subject to your will to have mercy, "have mercy on me," namely a sinner. He does not wish to contend, he does not seek to argue, but takes the short way: "have mercy." Also, he does not allege a cause for mercy, not the services he rendered to God, not the dangers he endured for him, but implores only the mercy of God; hence he says, "according to your great mercy." Dan. 9: "Not in our justifications do we prostrate our prayers before your face, but in your many mercies." And it should be noted that one can hope for divine mercy for a double reason. One reason is from the consideration of the divine nature; the other reason is from the consideration of the multitude of its effects. First, therefore, he shows that he hopes for the mercy of God from the consideration of the divine nature, because it is proper to the divine nature that it is goodness itself. Hence Dionysius says that God is the very substance of goodness. And Boethius in his work On the Trinity says the same. Hence this mercy of God is nothing other than goodness directed toward dispelling wretchedness. Therefore, when I consider that it is proper to goodness to dispel wretchedness, and that God is goodness itself, I confidently have recourse to mercy. And it is called great in its incomprehensibility, by which it fills all things. Ps. 32: "The earth is full of the mercy of the Lord." And it has a place in all things: for the just have preserved their innocence on account of the mercy of God. Augustine: "Lord, I attribute to your grace the evils I have not committed." Also, sinners have been converted to justice on account of the mercy of God. 1 Tim. 1: "I have obtained mercy." Also, those existing in sin have experienced the mercy of God. Lam. 3: "The mercies of the Lord are many; for we are not consumed." Also, it is called great in its sublimity, because "his mercies are above all his works"; for mercy does not signify in God a passion of the soul, but goodness directed toward dispelling wretchedness. Also great in its duration. Is. 54: "With everlasting mercy I have had compassion on you." Also great in its power, because it made God become man, brought God from heaven to earth, and made the immortal one die. Eph. 2: "But God, who is rich in mercy." Also great in its effect, because from every wretchedness a person can be raised through mercy. Ps. 85: "Your mercy is great upon me, and you have forgiven the wickedness of my sin" (Ps. 31). And therefore I confidently ask: "Have mercy on me, O God." The other reason is that in all things from the beginning of the world I have found the effects of your mercy. And therefore he says, "and according to the multitude of your mercies, blot out my iniquity"; as if to say: have mercy on me, according as you have had mercy in many ways and on diverse people. Hence Is. 63 says: "I will be mindful of the mercies of the Lord." Ps. 24: "Remember your mercies," etc. "Blot out my iniquity." Here he sets forth the effect of having mercy. Nathan said, 2 Sam. 12: "The Lord has taken away your sin," etc. And so he was secure about pardon; but he wished the sin to be totally eradicated. Now a twofold effect of sin remains: namely, the debt of punishment and the stain on the soul. First, therefore, he asks for the removal of the debt of punishment; and therefore, "wash me yet more from my iniquity." It should be known that in Jer. 17 it is said that the sin of Judah was written with an iron pen, with a point of diamond; in the likeness of a judge who writes the offense, which is preserved written for as long as he has the intention of punishing; but if he puts aside this intention, he does not preserve the record. And so it is said to be written with a diamond pen when the sin is not blotted out. And this is what he says, "blot out my iniquity," that is, do not impute my iniquity to me for punishment. Is. 43: "I am he who blots out your iniquities." Also, ibid. 44: "I have blotted out your iniquities like a cloud, and your sins like a mist."”

“Some monks called Euchites, or 'men of prayer', once came to Lucius in the ninth region of Alexandria. He asked them, 'What manual work do you do?' They said, 'We do not work with our hands. We obey St Paul's command and pray without ceasing' (1 Thess. 5:17). He said to them, 'Don't you eat?' They said, 'Yes, we do.' He said to them: 'When you are eating who prays for you?' Then he asked them, 'Don't you sleep?' They said, 'Yes, we do.' He said, 'Who prays for you while you are asleep?' and they could not answer him. Then he said to them, 'I may be wrong, brothers, but it seems to me that you don't do what you say. I will show you how I pray without ceasing although I work with my hands. With God's help, I sit down with a few palm leaves, and plait them, and say, 'Have mercy upon me, O God, after thy great mercy: and according to the multitude of thy mercies do away with mine iniquity' (Ps. 51:1). He asked them, 'Is that prayer, or not?' They said, 'It's prayer all right.' He said, 'When I spend all day working and praying in my heart, I make about sixteen pence. Two of these I put outside the door, and with the rest I buy food. Whoever finds the two pennies outside the door prays for me while I am eating and sleeping: and so by God's grace I fulfil the text, "Pray without ceasing" (1 Thess. 5:17).'”