SEFER CHOFETZ CHAIM
The Habitual Sinner
The prohibition of accepting loshon hora does not apply when the subject is known to regularly engage in the negative behavior under discussion. Thus, if on a number of occasions one has personally witnessed an individual commit a particular sin, he would be permitted to believe that the person committed that sin again. The Chofetz Chaim seems to suggest that one would even be permitted to believe the person has committed a different sin. When a person is known to totally disregard the Torah and its mitzvos one may certainly accept a report that he committed any sin.
If one is known to regularly transgress a particular sin out of temptation, one would be allowed to believe that he transgressed it again, but would be required to reject a claim that this time it was done maliciously.
SEFER SHMIRAS HALOSHON
Forgive and Forget
Even if all that one would gain through silent acceptance of humiliation is a lessening of punishment for a single sin, it would be well worthwhile. In fact, the gain is far greater, as stated in the Talmud:
Rava said: Whoever refrains from exacting his measure [i.e. from responding to the hurt caused him], [the Heavenly Tribunal] removes from him all his sins, as it is written, “He forgives transgressions and passes over sins” (Michah 7:18). Whose sin does He forgive? One who passes over sins [committed against himself] (Rosh Hashanah 17a).
Rava taught that even one’s willful sins committed in a state of spiritual rebellion, find atonement when one refrains from “exacting his measure.” However, to be worthy of such atonement, one must demonstrate a corresponding degree of forgiveness; that is, he must bear no ill will towards those who have caused him hurt, even when he knows for a fact that the hurt was inflicted maliciously.
Of course, such atonement is dependent upon the individual’s sincere resolve to refrain from committing these sins in the future.