—an example is the Prophet’s ﷺ saying: “Whoever deliberately lies about me, let him take his seat in the Fire.” (1)
2 – Āḥād (solitary): everything that does not reach the level of mutawātir.
In terms of strength it is divided into three classes: ṣaḥīḥ (sound), ḥasan (fair), and ḍaʿīf (weak).
• A ṣaḥīḥ report is one transmitted by an upright narrator of exact precision, through an unbroken chain, free from both irregularity and any critical flaw.
• A ḥasan report is one transmitted by an upright narrator of lesser precision, through an unbroken chain, likewise free of irregularity or critical flaw. When multiple independent chains support it, it ascends to the level of ṣaḥīḥ and is then termed ṣaḥīḥ li-ghayrihi (sound by virtue of corroboration).
• A ḍaʿīf report is whatever falls short of the conditions for ṣaḥīḥ or ḥasan. If it possesses several chains such that they reinforce one another, it rises to the rank of ḥasan and is called ḥasan li-ghayrihi (fair by virtue of corroboration).
All these categories constitute valid proof except the weak; the weak is not proof in itself, though there is no harm in citing it for corroboration and similar purposes.
Formulas of transmission
A ḥadīth involves both reception (taḥammul) and delivery (adāʾ).