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
Hadith terminology "with something, such as numerous chains of narration, strengthening it." Ibn Hajar's definitions indicate that there are five conditions to be met for a particular "hadith" to be considered "ṣaḥīḥ": A number of books were authored in which the author stipulated the inclusion of "ṣaḥīḥ hadith" alone. According to Ahl al-Sunna, this was only achieved by the first two books in the following list: "Ḥasan" ( meaning "good") is used to describe "hadith" whose authenticity is not as well-established as that of "ṣaḥīḥ hadith", but sufficient for use as supporting evidence. Ibn Hajar defines a "hadith" that is "ḥasan lithatihi"""ḥasan"