Rom 4:7

“And concerning the happiness of the man who has partaken of these, David says: "Blessed are they whose iniquities are forgiven, and whose sins are covered. Blessed is the man to whom the Lord will not impute sin." For, strictly speaking, there cannot any longer be reckoned ought against the martyrs, by whom in the baptism (of blood) life itself is laid down.”

“And he seems to be bringing a testimony beside his purpose. For it does not say, Blessed are they whose faith is reckoned for righteousness. But he does so on purpose, not through inadvertency, to show the greater superiority. For if he be blessed that by grace received forgiveness, much more is he that is made just, and that exhibits faith. For where blessedness is, there all shame is removed, and there is much glory, since blessedness is a greater degree both of reward and of glory. And for this cause what is the advantage of the other he states as unwritten, "Now to him that worketh is the reward reckoned not of grace;" but what the advantage of the faithful is, he brings Scriptural testimony to prove, saying, As David saith, "Blessed are they whose iniquities are forgiven, and whose sins are covered." What, he means, is it that you say? Is it that "it is not of debt but of grace that he receives forgiveness?" But see it is this person who is pronounced blessed. For he would not have pronounced him so, unless he saw him in the enjoyment of great glory.”

“What is forgiven is not retained in the mind, and what is covered does not come to light, and for that reason it is not counted against us.”

“For if he who receives forgiveness by grace is blessed, then far more blessed is he who has shown faith and been justified by it. Why, he says, do you hesitate over the fact that he receives forgiveness of sins by grace? You see that he who has received remission by grace is called blessed; for the prophet would not have called him blessed if he did not know that he possesses great glory: for blessedness is something exceedingly important and higher than righteousness itself; it is the summit of all the good things we receive from God.”

“Then when he says, blessed are they, he presents David's words containing the previous judgment and says that those whose sins are forgiven are blessed; consequently, they did not previously have good works, from which they obtained justice or happiness. But sin is divided into three classes: original, actual mortal, and actual venial. First, in regard to original sin he says: blessed are they whose iniquities are forgiven. Here it should be noted that original sin is called iniquity, because it is the lack of that original justice, by which in equity man's reason was subject to God, the lower powers to reason, and the body to the soul. This equity is removed by original sin, because after reason ceased to be subject to God, the lower powers rebel against reason and the body is withdrawn from obedience to the soul and subjected to decay and death. Hence: I was brought forth in iniquities (Ps 51:5). In both texts original sin is presented in the plural, either because of the multitude of men in whom original sin is multiplied or better because it virtually contains within itself all sins in some way. Such original sin is said to be forgiven, because the state of guilt passes with the coming of grace, but the effect remains in the form of fomes, or concupiscence, which is not entirely taken away in this life, but is remitted or mitigated. Second, in regard to actual mortal sin he says, and whose sins are covered. For sins are said to be covered from the divine gaze, inasmuch as he does not look upon them to be punished: you covered all their sin (Ps 84:3).”

“Obviously they are blessed, whose iniquities are forgiven without labor or work of any kind and whose sins are covered without any work of penitence being required of them, as long as they believe.How can these words apply to a penitent, when we know that penitents obtain the forgiveness of sin with much struggle and groaning? How can they be applied to a martyr, when we know that the glory of martyrdom is obtained by sufferings and pressures? But the prophet, foreseeing a happy time when the Savior comes, calls them blessed because their sins are forgiven, covered and not reckoned to them, and this without labor or work of any kind.”