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 clarify that term and not necessarily establish it. He also distinguished his book by responding to the positions of other scholars in a detailed manner. Ibn al-Ṣalāḥ mentioned in his introduction to the "Introduction" 65 chapters, each specific to a particular type or term of hadith terminology before saying that an even larger number was conceivable. He began by discussing "ṣaḥīḥ" (authentic) as the first category, and then "ḥasan" (good) as the second, "ḍa`īf" (weak) the third, "musnad" (supported) the fourth and so on. Ibn Jamāʻah, in his abridgement, divided these terms into four different categories according to subject (and