Parts or books of fiqh in this books are organized in the same way as al-Muqni’a.

Parts or books of fiqh in this books are organized in the same way as al-Muqni’a. The sources appealed to by al-Shaykh al-Tusi in this book are the Qur’an (the apparent or explicit meaning or connotations or implications thereof), absolutely authentic hadiths (such as al-khabar al-mutawatir, that is, frequently narrated hadiths, or ones with assuring evidence for their authenticity), consensus by Muslims or by Shiite scholars, and hadiths that are well-known among the companions of Imams (a).

Moreover, al-Shaykh al-Tusi has also cited contradicting hadiths, pointing to how to reconcile them with other hadiths or to weakness in them such as unreliability of their chains of narrators or the companions of Imams (a) refusing to act upon them. The book contains 393 sections and 13590 hadiths. In the epilogue of the book, al-Shaykh al-Tusi cites his mashikha, that is, people from whom he narrated the books that he cited in his book.

The Number of its Parts In his autobiography in his al-Fihrist, al-Shaykh al-Tusi enumerates 23 main parts or books of fiqh, saying that al-Istibsar and al-Nahaya have the same number of parts. However, the parts of al-shahadat (witnessing or testimony) and al-at’ima wa al-ashriba (eating and drinking) are only independently discussed in the latter two books. Moreover, Tahdhib al-ahkam contains an independent book of al-ziyarat (pilgrimages) that is absent in the other two works.

Therefore, Tahdhib al-ahkam contains 21 parts or books of fiqh, and the ones mentioned in al-Fihrist are combinations of parts contained in Tahdhib al-ahkam, al-Nahaya and al-Istibsar. According to enumerations of the published version of book in Najaf, the book contains 409 sections (28 of which are repetitive) and 13988 hadiths, but according to enumerations of Muhaddith al-Nuri, the book contains 393 sections and 13590 hadiths.

The difference is rooted in mistakes in enumerations or disputes about some parts or hadiths being independent or not. Purpose for Writing In the preface to Tahdhib al-ahkam, al-Shaykh al-Tusi writes that one of his friends talked to him about apparently contradictory hadiths in Shiite sources, pointing that this has led to strong criticisms by opponents of Shiism and disbelieving Shiism by some ignorant Shiites.