Hadith.

Bismi'llah ar-Rahman ar-Rahim...for the sake of Prophet Muhammad saws and Sheikh Nazim may Allah protect his secret.

THE ORIGIN AND DEVELOPMENT OF HADITH

Hadith is a verbal noun derived from the Arabic root verb hadatha which means to occur, to relate, to speak, and to report. Thus, the term Hadith literally means "communication, story, conversation: religious or secular, historical or recent." The term Hadith in its literal sense appears both in the Qur'anic texts and Hadith literature. For example, in the Qur'an we come across this citation:"Has the Hadith (story) of Musa reached you."
In the Hadith literature it is reported that the Prophet Muhammad (Sallallaahu Alayhi Wasallam) said: "The best Hadith (communication) is the Book of Allah."
It may be appropriate to point out that the term Hadith also has the connotation of 'new' being used as an antonym of 'old' (qadim). The technical meaning of the term Hadith has been defined by the fuqaha' (Muslim jurists) as "the words and deeds of the Prophet Muhammad (Sallallaahu Alayhi Wasallam)", while the muhaddithun (scholars of Hadith) define it as "the words, practices, tacit approval of the Prophet (Sallallaahu Alayhi Wasallam), or description of his sifat (features) meaning his physical appearance."
Hadith and SunnahClosely connected to the term Hadith is the term Sunnah. Sunnah (pl. Sunan) is a verbal noun derived from the Arabic root verb sanna which means to introduce, prescribe or establish. The technical meaning of the term Sunnah is the mode of life of the Prophet (Sallallaahu Alayhi Wasallam).
The two terms Hadith and Sunnah are translated as Traditions of the Prophet (Sallallaahu Alayhi Wasallam). They are often interchangeably used but nevertheless there is a subtle difference between the two terms. In short, Sunnah represents what was practised by the Prophet (Sallallaahu Alayhi Wasallam), while hadith is the record of what the Prophet (Sallallaahu Alayhi Wasallam) said and practised. Thus, a Hadith may not contain any Sunnah as in the following example:"The best of you is the one who studies the Qur'an and teaches it".
Or, on the other hand, it may contain one or more Sunnah as, for example, in the Ahadith (sing. Hadith) dealing with matters pertaining to the mode of 'ibadah (worship) like the Sunnah of the Salaah (obligatory prayers), the rites of Hajj (pilgrimage), the etiquette of siyaam (fasting) etc.
Muslim jurists define Sunnah as "what has been transmitted on the authority of the Prophet (Sallallaahu Alayhi Wasallam) which includes his saying, practice and tacit approval." The muhaddithun (scholars of Hadith) define this term as "that which has been reported on the authority of the Prophet (Sallallaahu Alayhi Wasallam) and includes his saying, practice, and tacit approval, and, inter alia, description of his physical appearance, moral character and way of life, before prophethood was confirmed upon him or after that.
In effect, Sunnah is primarily of three kinds:
1. Al-Qawl i.e. verbal teaching of the Prophet (Sallallaahu Alayhi Wasallam). For example, Hadrat Abu Hurayrah (Radhiallaahu Ánhu) reported that the Prophet (Sallallaahu Alayhi Wasallam) said: 'The best house, amid the Muslim community, is one in which an orphan is treated well, and the worst house is one in which an orphan is ill-treated."2. Al-fi'l i.e. practical teaching done by the Prophet through practical demonstration like the method of performing the Wudhu (ablution), Salah (obligatory prayers), the mode of siyam (fasting.) and the per performance of hajj (pilgrimage).3. Al-Taqrir i.e. tacit approval which may be explained as an act done in the presence of the Prophet (Alayhis salaam)(Sallallaahu Alayhi Wasallam) and he either approved of it or censured it. For example, the Prophet (Sallallaahu Alayhi Wasallam) forbade his Companions (Radhiallaahu Ánhu) from wearing silk and gold rings.

Continue reading here.

Further information here.