and to caution people; an example is the critical appraisal of ḥadīth narrators.

4. al-Nawawī said: “Know that ghībah (backbiting) is permissible when it serves a legitimate Sharīʿah purpose that cannot be attained except through it.” He then cited among those purposes: warning Muslims against harm and offering them sincere advice. This takes various forms, one of which is disparaging unreliable narrators and witnesses—an act permitted by the unanimous agreement of the Muslims; indeed, it is obligatory. Another is identifying a person by a nickname when he is known only by it, such as al-Aʿmash (“the bleary-eyed”), al-Aʿraj (“the lame”), al-Aṣamm (“the deaf”), and the like. Using such epithets to belittle someone is forbidden, however, and if he can be recognized without them, that is preferable.

5. The creed of Ahl al-Sunnah wal-Jamāʿah concerning deceased Muslims is that we hope Allah will grant the doer of good his full reward, show him mercy, and spare him punishment, while we fear that the evildoer may be seized for his sins. We do not declare anyone to be in Paradise or Hell, except those for whom the Prophet ﷺ himself bore witness. It is unlawful to entertain ill thoughts about a Muslim whose outward conduct is upright; but in the case of one whose conduct openly displays wickedness, there is no blame in being suspicious of him.