Hadith of the Quran and Sunnah accept the authenticity of the related Hadith of the two weighty things ("Hadith al-Thaqalayn"). In this hadith, Muhammad referred to the Qur'an and "Ahl al-Bayt" ('people of the house', Muhammed's family) as the two weighty things. Although the hadith is accepted by both Sunnis and Shi'as, the two groups differ on the exact wording of what Muhammad said, as well as how to interpret these words. The Shi'as use the Hadith of the two weighty things to prove their claim that Muhammad meant for all his successors to be from his own family ("Ahl al-Bayt"). The Sunnis reject this view
Introduction to the Science of Hadith category, which comprises 21 types, relates to the names of the narrators. This includes the definition of a "ṣaḥābī" (companion), a "tābi`ī" (follower), the time periods of narrators, names and paidonymics among others. Later scholars included additional types of hadith in their own works, with some almost reaching 100. The "Introduction" became the basis for subsequent books in hadith terminology. A number of subsequent scholars followed Ibn al-Ṣalāḥ in the ordering of his book, including al-Nawawī, Ibn Kathīr, al-ʻIraqi, al-Bulqīnī, Ibn al-Jamā`ah, al-Tabrīzī, al-Ṭībī and al-Zirkashī. In many instances this influence was direct, with numerous scholars authoring books indicating its