Musar su Salmi 5:5

The eighth: "He suppresses our iniquities" - behold, the Holy One, blessed be He, acts with Israel with this trait, and that is the secret of the suppression of iniquities. As behold the commandment, 'it is like when it blossoms, its bud arises' and it pierces and climbs until no end, to enter in front of Him, may He be blessed. But the iniquities, however, do not have passage there, God forbid. Rather, He suppresses them, such that they not enter - as it is written (Psalms 5:5), "evil does not dwell [with] You (yegurcha)"; evil shall not dwell in Your domicile (megurcha). If so, the iniquity does not enter inside. And from this reason, "There is no reward for a commandment in this world" (Kiddushin 39a) - as [the commandments] are in front of Him, may He be blessed. And how can He give him from that which is in front of Him - a spiritual reward - in the world that is physical? And behold, the entire world is not worth one commandment and the satisfaction [from it] in front of Him. And for this reason, He does not take the bribe of commandments. The metaphor for this is that the Holy One, blessed be He, does not say, "He did forty commandments and ten sins; there remain thirty and the [other] ten go [away] with the ten" - God forbid! Rather, even if he was a completely righteous one and he committed one sin, it is similar in front of Him as if he burned the entire Torah, until he satisfies his debt. And afterwards, he can receive the reward for all of his commandments. And this is a great kindness that the Holy One, blessed be He, does with the righteous ones - that he does not reduce [the reward], as the commandments are very important and climb until [they reach] in front of Him, may He be blessed. And how could He reduce from them on account of sins - as the repayment of sins is from the share of Geihinom, from that which is disdained; whereas the reward of the commandments is from the honored, the radiance of the Divine Presence. How could these be reduced [on account of] those? Rather, the Holy One, blessed be He, collects the debt of the sins and pays the reward of all of the commandments. And this is [the meaning of] "He suppresses our iniquities" - that the iniquities do not intensify in front of Him, like the commandments. Rather He suppresses them that they should not rise and not enter - even as He is supervising over the ways of a man, good and bad. Nonetheless, He does not suppress the good, but rather it blossoms and climbs until [it grows] very much. And [so] one commandment is grouped together with [another] commandment and a great edifice is built, and a fine suit [is formed]. But iniquities do not have this special quality, but He rather suppresses them, that they should not have this success, and [not] enter inside [in front of Him].

Explanation of the words of iniquity of four groups:
Our Rabbis, may their memory be blessed, said (Sotah 42a), “Four groups will not greet the Divine Presence: The group of scoffers, the group of liars, the group of flatterers, and the group of slanderers. The group of cynics, as it is written (Hosea 7:5), ‘He draws His hand from cynics’; the group of liars, as it is written (Psalms 101:7), ‘he who speaks falsehood shall not dwell before My eyes’; the group of flatterers, as it is written (Job 13:16), ‘that a flatterer cannot come before Him’; the group of slanderers, as it is written (Psalms 5:5), ‘For You are not a God who has pleasure in wickedness, evil shall not sojourn with You.’”

Chazal have explained that the class of slanderers is one of four classes who do not behold the Shechinah, viz. (Sotah 42b): "R. Yirmiyah b. Abba said: Four classes do not behold the Shechinah: the class of flatterers, the class of liars, the class of scoffers, and the class of slanderers … The class of slanderers, viz. (Psalms 5:5): 'For You are not a G-d that desires wickedness; evil will not sojourn with You.' You are righteous, O L-rd; evil will not sojourn in Your dwelling place.'" This section deals with the sin of lashon hara, as Rashi explains there. And the speaker of lashon hara is even called "evil," as we find in Aggadath Mishlei on the verse (Mishlei 12:20): "There is deceit in the heart of plotters of evil" — R. Chamma b. R. Chanina said: "One who speaks with his friend and eats and drinks with him and speaks lashon hara against him, the Holy One Blessed be He calls him 'evil,' etc." He is also judged in the fourth level of Gehinnom for this sin, as stated in Midrash Hane'elam on Ruth.