Hadith of Umar's ban on hadith decision of Muhammad was rescinded later in his ministry. During Umar's reign as Caliph, hadith were in fact being recorded. On the other hand, some sources dispute this account, and claim that it was Umar himself who was the first person to ban hadith collection - a view also upheld by Shias. Certainly during his rule Umar strictly followed the policy of banning the hadith and he prohibited reporting and transmission of hadith altogether. Whenever he sent a group to a city, he would prohibit them from narrating hadith. This ban continued through the caliphate of the Rashidun caliphs into
Introduction to the Science of Hadith al-Ṣalāḥ, in his "Introduction", codified the terminology established by those scholars before him based upon his reading of their works. He did so by citing some of those scholarly statements in the earlier works and deducing from them common terms and definitions in the manner of a scholar authoring a book of "fiqh" (jurisprudence). In this manner, his book was based upon those principles established by the earlier hadith specialists combined with some elements of "fiqh". An example of this would be the inclusion of the division of hadith into "mutawātir" and "āḥād". He therefore only mentioned the statements of