The Eighth Type: Evil Opinion
It is a result of envy, and it is a disease and a temptation of Satan. This means that when you think that your believing brother has done a forbidden deed or neglected an obligation without a confession from him or without a clear evidence that is considered an approved certificate or something similar to it according to Islamic Law, like large fame or reputation. It is forbidden without doubt. It is this thought that is considered unanimously, as abominable. An explanation should be made when possible. The evidence to prove that it is an obligation is His saying, exalted be He; {Why then didn’t the believers, men and women, when you heard it (the slander), think good of their own people} (Q. 24:12). Then, having a good opinion is not possible without an explanation. It is one of the reasons that require the grudge. So fighting it is an obligation, but if it is not eliminated from the heart, then the one who had a bad opinion of him should be investigated so that he either confesses or repents. Allah may guide him by the hands of who does it. It is one of the best matters on earth that has ever seen the light of sun.
Or he confesses and declares his rebellion and refusing to repent, so that the thought turns to be certitude. Otherwise this sign that requires the bad opinion turns to be false. But in case of the opinion, one apologizes and denies then he cannot be accused of lying except by certitude. The evidence of this is: {Say: “He listens to what is best for you; he believes in Allah has faith in the believers”} (Q. 9:12). The believer—when he finds a mistake from his brother—should hide it and not spread it. But if he rebelled and refuses to repent, then you have to be wary of him.