The knowledge of the Sunnah has reached us via means of the ḥadīth of the Messenger of Allāh (ﷺ). The ḥadīth refers to a comibnation of a text and a chain of narration (isnād), beginning from the Prophet (ﷺ) and ending at the scholar who recorded that ḥadīth.

The Sunnah refers to the commands, prohibitions, sayings, actions, and tacit approvals of the Messenger of Allāh (ﷺ).

The whole of the Sunnah falls under the command of Allāh in His Book:

“Whatsoever the Messenger gives you then take it and whatsoever he prohibits you from then refrain from it.”
[Sūrah al-Ḥashr 59:7]

The tābiʿī, Imām al-Ẓuhrī said:

“Clinging to the Sunnah is to be saved, as Imām Mālik said, ‘like the Ark of Nūḥ.’ He who embarked upon it was saved and he who did not was destroyed.” [al-Dārimī]

The knowledge of the Sunnah has reached us via means of the ḥadīth of the Messenger of Allāh (ﷺ). The ḥadīth refers to a combination of a text and a chain of narration (isnād) beginning from the Prophet (ﷺ) and ending at the scholar who recorded that ḥadīth. There are a number of conditions that the ḥadīth must meet based upon which it is divided into two broad categories ṣaḥīḥ (authentic) and dāʿīf (weak). The authentic ḥadīth is that ḥadīth from which beliefs and legislation can be derived. The weak ḥadīth does not allow us to derive beliefs or legislation from it.