Musar su Salmi 51:4

And behold that there are many levels of repentance. It is true that you will find forgiveness for any repentance. However the soul will only find complete purification - to be as if the iniquities never had been - when a person purifies his heart and prepares his spirit, as will be explained. And so is it written (Psalms 32:2), "Happy is the man whom the Lord does not hold guilty, and in whose spirit there is no deceit." And it is like the matter of a garment that needs washing: For a little washing will be effective to remove its soiling. However, it will [only] whiten according to the amount of washing. And so is it written there (Psalms 51:4), "Wash me thoroughly of my iniquity." And the soul will be washed from iniquity according to how you wash its heart, as it is stated (Jeremiah 4:14), "Wash your heart clean of wickedness, O Jerusalem." And our Rabbis, may their memory be blessed, said (Avodah Zarah 19a), "'Happy is the man who fears the Lord' (Psalms 112:1) - when he is still a man." This means to say that the most elevated repentance of a man is in the days of his youth - [when] he overcomes his impulse when his strength is still with him. However any repentance is effective, as it is stated (Psalms 90:3), "You return man to dust; You said, 'Return you mortals!'" And our Rabbis, may their memory be blessed, said (Yerushalmi Chagigah 2:1), "Until the soul turns to dust."

The ninth: "And You will hurl into the depths of the sea all of their sins" - this is a good trait of the Holy One, blessed be He. As behold, Israel sinned; He delivered them into the hand of Pharaoh, and they repented. Why [should] he punish Pharaoh? And likewise Sancheriv; and likewise Haman and those similar to them. The Holy One, blessed be He, is not only assuaged to say, "They have repented. If so, let them not have any more evil. If so, let Haman withdraw from them," or Pharaoh, or Sancheriv. This does not suffice. Rather, he puts the travail of Haman back on his head; and likewise Pharaoh; and likewise Sancheriv. And the reason for this practice is the secret of "And the goat carries upon him all of their iniquities to a desolate land" (Leviticus 16:22). And its explanation is that it carries the actual sins. But this is very difficult: And shall Israel sin and the goat carry [it]? Rather [this] trait is like this: A person confesses [sins], and his intention in the confession is to receive purification upon himself; like the matter that David stated (Psalms 51:4), "Wash me thoroughly from my iniquity." And so, in our saying, "Purge [me] in Your great mercy," [one] is only praying that the afflictions be light, such that there not be a hindrance of Torah [study]; and this [is also the intention of] that which we say, "But not through bad (harsh) afflictions." And so, in his saying, "And You are righteous about all that happens to me" - he intends to truly accept afflictions with a pleasant countenance, in order to atone; as there are iniquities that [only] afflictions purge or that [only] death purges. And such is the trait: As soon as this one confesses in his prayer - they explained in the Zohar in Parshat Pekudei (p. 262b) that this is the portion of Samael, similar to the goat. What is his portion that the Holy One, blessed be He, decreed for him? Afflictions. And [so] Samael immediately arrives there and goes and collects his debt. And behold, [this is] the goat carrying the iniquities - that the Holy One, blessed be He, gives him authority to collect his debt, and Israel is [thus] purified. But, behold, it all devolves upon Samael. And the reason is because the Holy One, blessed be He, decreed upon His world, that anyone who does this, will be nullified. And this is the reason of, "and you shall kill the beast" (Leviticus 20:15). And likewise the stone of the commandment of those stoned; and the sword of the commandment of those killed, require burial (Sanhedrin 45b) to nullify their existence and power after their judgement is finished.

And the penitent should also pray to God to erase his transgressions like a fog, and his sins like a cloud; and that He desire him, accept him and listen to him as if he had not sinned - like the matter that is written in the words of Elihu about a penitent after [he has suffered] afflictions (Job 33:26), "He prays to God and is accepted by Him." For it is likely for the iniquity to be forgiven and he be redeemed from all afflictions and from all decrees, but God [still] not desire him and not want to accept an offering from him. And it is the desire of the righteous from [their] successes, to incline God's will towards them and that He should desire them. And his will is [for] real everlasting life and for the great light that includes all of the pleasant things - like the matter that is stated (Psalms 30:6), "when He is pleased there is life." And it [also] stated (Psalms 80:20), "O Lord, God of hosts, restore us; shine Your countenance that we may be delivered" - and our Rabbis, may their memory be blessed said "(Midrash Tehillim 80), "We have nothing besides the shining of Your countenance." And that is the matter of [His] desire - and we have already mentioned this and explained it. Therefore you will see in the prayer of David at the time of [his] repentance after he said (Psalms 51:4), "Wash me thoroughly of my iniquity, and purify me of my sin," [that] he prayed further about the desire - that God's desire, may He be blessed - for him to be like before the sin. So he said (Psalms 51:13), "Do not cast me out of Your presence, or take Your holy spirit away from me." Afterwards he prayed and said (Psalms 51:14), "Let me again rejoice in Your salvation" - that the miracles of God and His salvation be found with him, and that the spirit of God would come upon him as at first. And afterwards he [continued], "and a generous spirit sustain me." Its explanation is - behold I have been lessened because of my transgressions and am not fitting to be a prince, and for Your holy arm to be revealed upon Me. And even if you have lifted (forgiven) the iniquity of my sin, I am not worthy to be beloved and acceptable as in earlier times. Yet sustain me with a generous spirit; for there is no end to Your generosity and Your goodness. And [the word,] spirit, comes lacking a [letter,] bet (in front of it, which would mean, with the spirit), like [in] (Genesis 27:37), "sustained him grain and wine" (which is to be understood as if grain was preceded by a letter bet, meaning "with grain, etc."). And Hosea, peace be upon him, said about this matter (Hosea 14:5), "I will heal their affliction, I will take them back in generous love." The matter of generous love is like the matter that David said, ["and a generous spirit] sustain me."