Musar su Salmi 38:19

The fifth principle is worry: As he will worry and fear from the punishment of his iniquities. For there are iniquities for which the repentance has the atonement depend upon cleansing afflictions, as it is stated (Psalms 38:19), "I acknowledge my iniquity; I am fearful over my sin." The content of grief is about the past, whereas the content of worry is about the future. And he will also doubly worry - maybe he is falling short in his obligation of repentance with pain, bitterness, fasting and crying. And even if he has multiplied the pain and multiplied the crying, he should crawl and fear - maybe corresponding to this had he multiplied his guilt; so that all of his affliction and having his soul cry in its fast did not fill his measure. And one who examines the greatness of the service to the Creator upon his creatures and that there is no end to the evil of one who rebels against His word [will know that even with] all of what he adds to his service and in the ways of repentance, is it not small? Behold it is like a little in his eyes. And King Solomon, peace be upon him, said (Proverbs 14:16), "A wise man is afraid and turns away from evil." And its explanation is that even though a wise man turns away from evil with all of the efforts of his ability, he should crawl and fear - maybe he did not complete his measure, and he was not careful according to the standard of what needs to be done. And like this is (Proverbs 28:6), "than a rich man whose ways are crooked" - even though he is rich. And likewise did our Rabbis, may their memory be blessed, say in Yilamdeinu (Tanchuma, Lech Lecha, 15), "Do not explain [it as] 'A wise man is afraid and turns away from evil'; but rather, 'A wise man turns away from evil and is afraid.'" And the end of the verse (Proverbs 14:16) proves this - "but a fool rushes and is confident." He states abut the traits of a fool, that they are the opposite of the traits of a wise man. For a fool rushes, but is nevertheless confident that iniquity and damage will not come to him. Yet the angry person is given to sins and open to damages, as it is stated (Proverbs 29:22), "A hot-tempered man commits many offenses." And it is [also] stated (Proverbs 25:28), "Like an open city without walls is a man whose temper is uncurbed."

Tears come from sorrow and great worry. And we have learned that "the gates of tears are not locked" (Baba Mezi'a 59a). And it is written, "Mine eyes run down with rivers of water because they observe not Thy Torah" (Ps. 119:136). And it is written, "For I do declare mine iniquity : I am full of care because of my sin" (Ps. 38:19). A man ought always to be concerned with what has passed, worry as to what lies ahead and always be fearful that perhaps he will not fulfill the full measure of repentance. "Happy is the man that feareth always" (Prov. 28:14).

The fifth principle of repentance is worry. One should worry about the punishment of his sins, for there are sins where repentance holds the atonement in suspense and only afflictions cleanse away the wrong (Yoma 86a), as it is said, "For I do declare mine iniquity; I am full of care because of my sin" (Ps. 38:19). And what is the difference between sorrow and worry? Sorrow is for what has already taken place, while worry concerns the future. And a person who has sinned should always worry whether he has fallen short in the matter of repentance and has not completed the full measure of repentance. And he should worry lest his evil inclination overpower him. As our Sages, of blessed memory, said, "Do not trust in yourself until the day of your death" (Aboth 2:4).