In what cases is backbiting permissible?

One should strive to attend gatherings of relatives and neighbors if they are for good, maintaining kinship ties, and fostering good neighborliness. However, if such gatherings involve sin, like backbiting and tale-bearing, a person should denounce it if possible; otherwise, they must leave the gathering. Socializing is better than isolation, provided there is safety from temptations. But if one isolates themselves due to an inability to prevent evil, that is permissible. The optimal approach is not to refrain from a right that people are entitled to, nor to become engrossed in falsehood that is not obligatory upon them. Thus, one should be with people in good and apart from them in evil, striking a balance between withdrawal and closeness, for the best of matters are their moderate ones.