Hadith are "expressed in Muhammad's words", whereas the latter are the "direct words of God". A "hadith qudsi" need not be a "sahih" (sound hadith), but may be "da‘if" or even "mawdu‘". An example of a "hadith qudsi" is the hadith of Abu Hurairah who said that Muhammad said: When God decreed the Creation He pledged Himself by writing in His book which is laid down with Him: My mercy prevails over My wrath. In the Shia school of thought, there are two fundamental viewpoints of Hadith: The Akhbari view and the Usuli view. The Usuli scholars stress the importance of
Introduction to the Science of Hadith chapters, each covering a hadith related issue. The first 33 chapters describe the various technical terms of hadith terminology which describe the conditions of a hadith's authenticity, or acceptability as a basis for Islamic jurisprudence. The following chapters relate to the "isnād", or chain of narration. Next are a series of chapters pertaining to the etiquette to be observed by hadith scholars and manners of transcription. The last chapters describe various issues relating to the narrators of hadith including naming conventions. Ibn al-Ṣalāḥ began the "Introduction" as a series of lectures he dictated to his students in Damascus ending in