Thus the original intention of al-Tusi had been to write a...

Thus the original intention of al-Tusi had been to write a commentary on al-Muqni'a of al-Mufid. However, he makes it clear in his introduction that his work would only concern the furu' of Islamic law, i.e. the practical regulations for carrying out the sharia, the holy law of Islam.

He said: "I went first to the chapter which was connected with ritual purity (tahara), leaving aside the (chapters) which preceded it, which were about the Unity of God (tawhid), Justice ('adl), Prophethood (nubuwwa) and the Imamate (imama), because the explanation of these would be too lengthy, and also because it was not the intention of this book to elucidate the principles of religion (al-usul).[^6] In his introduction, al-Tusi makes it clear that the principal motive for writing this work and limiting it to the furu', was the great differences which were arising in Shi'ite traditions.

He mentions that these differences were being used against the Shi'a by their opponents as an argument against the truth of Shi'ite beliefs. The situation had become so critical that al-Tusi reports al-Mufid's account of one Shi'ite adherent who had left the community because of the contradictory traditions. Al-Tusi set himself the task of analysing the traditions concerned with furu', explaining which traditions were deficient and reconciling apparent contradictions in sound traditions.

He used al-Mufid's al-Maqni'a as the basis for this task.[^7] However, he did not only deal with the traditions used in al-Muqni'a; he analysed many more traditions which he included at the end of various sections, appendices of traditions not mentioned by al-Mufid, which he also discusses. The method used is to quote the traditions and then al-Mufid's comments on them. This is often followed by al-Tusi's explanation of al-Mufid's comments.

Sometimes, it is not always clear whether the explanation belongs to al-Mufid or al-Tusi. However, he quite often makes it clear that it is al-Mufid when he says: "Al Shaikh said..." But sometimes a discussion is introduced by the ambiguous terms: "He said..." This could refer to either al-Mufid or al-Tusi. In the appendices al-Tusi makes it quite clear that he is making the comments, for he says: "Muhammad b.

al-Hasan said..." The discussions on the traditions are sometimes of considerable length.