Allah does not like negative thoughts to be voiced—except by those who have been wronged.41 Allah is All-Hearing, All-Knowing.
Allah loveth not that evil should be noised abroad 654 in public speech, except where injustice have been done; for Allah is He who heareth and knoweth all things.
654 We can make a public scandal of evil in many ways. (1) It may be idle sensation-mongering: it often leads to more evil by imitation, as where criminal deeds are glorified in a cinema, or talked about shamelessly in a novel or drama. (2) It may be malicious gossip of a foolish, personal kind: it does no good, but it hurts people's feelings. (3) It may be malevolent slander or libel: it is intended deliberately to cause harm to people's reputation or injure them in other ways, and is rightly punishable under all laws. (4) It may be a public rebuke or correction or remonstrance, without malice. (1), (2) and (3) are absolutely forbidden. (4) may be by a person in authority; in which case the exception applies, for all wrong or injustice must be corrected openly, to prevent its recurrence. Or (4) may be by a person not vested with authority, but acting either from motives of public spirit, or in order to help some one who has been wronged; here again the exception will apply. But if the motive is different, the exception does not apply. (4) would also include a public complaint by a person who has suffered a wrong; he has every right to seek public redress.
God does not like any evil to be mentioned openly, unless it be by him who has been wronged (thereby) 161 And God is indeed all-hearing, all-knowing,
161 As some of the commentators (e.g., Razi) point out, this may refer to giving currency to earlier sayings or deeds of the repentant sinners - both hypocrites and outright deniers of the truth - mentioned in the preceding two verses: an interpretation which seems to be borne out by the context. However, the above statement has a general import as well: it prohibits the public mention of anybody's evil deeds or sayings, "unless it be by him who has been wronged (thereby)"- which also implies that evil behaviour which affects the society as a whole may be made public if the interests of the wronged party - in this case, the society as such - demand it.
41 i.e., Allah does not like talking about people behind their backs—except when someone who has been wronged seeks counselling or assistance from authorities.