The Sunnah refers to the commands, prohibitions, sayings, actions and tacit approvals of the Messenger of Allaah (صلى الله عليه وسلم). The whole of the Sunnah falls under the command of Allaah in His Book:
“Whatsoever the Messenger gives you then take it and whatsoever he prohibits you from then refrain from it.” [Sooratul-Hashr 59:7]
The taabi’ee, Imaam az-Zuhree said:
“Clinging to the Sunnah is to be saved, as Imaam Maalik said, ‘like the Ark of Nooh.’ He who embarked upon it was saved and he who did not was destroyed.” [ad-Daarimee]
The knowledge of the Sunnah has reached us via means of the hadeeth of the Messenger of Allaah (صلى الله عليه وسلم). The hadeeth refers to a combination of a text and a chain of narration (isnaad) beginning from the Prophet (صلى الله عليه وسلم) and ending at the scholar who recorded that hadeeth. There are a number of conditions that the hadeeth must meet based upon which it is divided into two broad categories saheeh (authentic) and da’eef (weak). The authentic hadeeth is that hadeeth from which beliefs and legislation can be derived. The weak hadeeth does not allow us to derive beliefs or legislation from it.