Criticism of Hadith thus provides "certainty of knowledge" of what Muhammad said, in fact it is only the much rarer subset of sahih -- "mutawatir" hadith -- that provide certain knowledge. "Mutawatir" means the report "of a large number of narrators whose agreement upon a lie is inconceivable. This condition must be met in the entire chain from the origin of the report to the very end." However, according to Wael Hallaq, "the bulk of hadith with which the traditionists dealt, and on the basis of which the Jurists derived the law" were known as "ahad" — i.e. non-"mutawatir" hadith; Hadith without "textually
Hadith terminology "musnad" ( meaning "supported") "hadith" as: A "musnad hadith" should not be confused with the type of "hadith" collection similarly termed "musannaf", which is arranged according to the name of the companion narrating each "hadith". For example, a "musnad" might begin by listing a number of the "hadith", complete with their respective "sanads", of Abu Bakr, and then listing a number of "hadith" from Umar, and then Uthman ibn Affan and so on. Individual compilers of this type of collection may vary in their method of arranging those Companions whose "hadith" they were collecting. An example of this type of