The Tebyan exegesis is one the fifth century commentaries, written with a theological approach. TUSI's endeavour for strengthening Shiite tenets in it, verifies his focus on this issue. The rather priority of theology compared to other sciences in TUSI's era and current dogmatic debates, along with the authoritative status of prominent Shiite scholars such as SHEIKH Mufid, Seyyed Murteza and SHEIKHTUSI himself all had great influence on this commentary. The vast narration of the Mutazili views such as those of Abu Ali Jubayi, Rummani, Balkhi, Ka' bi and Muhammad Bahr Isfahani fulfilled this end. Both for the rational methodology of Muhammad Bahr Isfahani and Rummani and for the dogmatic principles common with Mutazila, TUSI has preferred the Mutazili's opinions and narrated them. Although in quite a few occasions has also criticized their believes and negated them.

Imamate has been known as a fundamental teaching in shiism. There have been presented various reasonings on behalf of the docrine in the history of Shiism. In the paper, thereasonings of Baghdadian school, established by the most famous theologians and jurisprudents SHEIKH Mofeed, seyyed Mortaza and SHEIKHTUSI, have been studied. In this way, the Shiite conception of Imamate has been clarified, the agreement of the Baghdadian conceptions has been explained and the reasonings have been evaluated.

SHEIKH TUSI’s Al-Rijal, being compiled in thirteen chapters and including 8900 narrators, has been written with the aim of counting the narrators of the immaculate imams and determining their ranks.The paper is an attempt to find out the principles and methods on which SHEIKH’s classification of the narrators’ position was based.Although SHEIKH has not sought to state reliability, weakness, and to modify the matters in detail, his Rijali method, in general, is based on refraining from undermining the vulnerable people or, ultimately, from weakening the weak. And it is the fact originated from his moderate mood and, at the same time, being partially related to the historical situation of his era i.e. the early arrival of the Seljuk’s prejudiced in Shafei religion that led to the intension of conflicts between Shia and Sunni. The result of his attempt in this delicate situation is documentation of some narrations from the Sunnis and different Shia sects to reduce some dimensions of these damages. Therefore, his Rijali circle has been considerably expanded. It should be mentioned that referring to only the name of someone in this book does not mean that one could make sure that he is Imami or even Shiite.

The interpreters’ first step in authoring works of interpretation was to collect the narrations that directly or indirectly dealt with the interpretation of the Quranic verses. These are the narrations from the Prophet (p.b.u.h.) or the Imams (a.s.) that are cited in interpreting the verses of the Quran. This method was often used to interpret the Holy Quran during the presence era and afterwards until the 4th century (A.H.) when the Islamic world came upon a revolution in interpretation sciences and with the growth of rationalism, especially in the School of Baghdad, this achievement was expanded and crossed borders. Interpreters embarked upon ijtihad and, hence, they gained access to interpretational narrations in addition to other resources. Among these interpreters, SHEIKH TUSI has extensively relied on narrations with a single transmitter in al-Tebyan fi Tafsir al-Quran although he has pointed out in the same work of interpretation that such narrations lack authority. These narrations often lack chain of transmission but they have been used in explaining the issues related to Quranic sciences, explaining the verses of the revealed prescripts, evaluating other narrations, endorsing or supporting the views of interpreters, and explaining theological issues. Sometimes, SHEIKH TUSI has relied on documentational criticism and some other times on textual criticism but he has been mainly involved with textual criticism.

The issue of prophecy as the second doctrinal principle has a special place in the system of thought and belief because the prophet is the means of human evolution and has reached the truth of humanity. In this research, an attempt has been made to compare and analyze the view of SHEIKH TUSI, one of the great theologians of Baghdad in the 4th and 5th centuries AH, with Mulla Sadra, an 11th century philosopher from Isfahan school, in order to highlight the role of philosophy in explaining important issues like prophecy. SHEIKH TUSI with the help of the theological rule of grace proves that the existence of a prophet is obligatory. Since human intellect is unable to comprehend some deeds, the Almighty God has compensated this shortcoming by sending a prophet to guide human beings. With this rational explanation, SHEIKH TUSI has considered the prophet as an example of the rule of grace. It is noteworthy that he has limited the necessity of the existence of a prophet only to the dimension of legislating divine laws and has not considered regulation of people's political and livelihood affairs to be obligatory for the prophet. This attitude is due to the limitation of his intellectual horizon. However, with the help of philosophy, Sadra Hakim has paid attention to this issue from 4 different angles and has been able to prove the necessity of the existence of a prophet with a deeper vision. In the field of ontology, he has considered the consistency of existence dependent on the existence of a prophet (a perfect human being) and in the field of epistemology, his book has referred to Man for achieving knowledge and introducing obedience to the prophet’s commands both scientifically and practically. He has also paid attention to the social life of human beings and their worldly and livelihood problems and considered it possible to meet these needs under the rule and leadership of a prophet. The event of reforming the worldly life of human beings has been considered as a prelude to happiness in the hereafter and as one of the duties and missions of the prophet. Sadra's attention to the dimension of love and attainment of spiritual pleasure has shown his attention to human needs, which, of course, are satisfied only by obeying the prophet and connecting with him, who is a complete mirror of the divine perfection. These salient differences in the philosophy of prophecy stem from differences in the principles and methods of the two thinkers. The most important differences between these two scholars are the differences in the purpose of the existence of a prophet and their attitudes towards human truth with the explanation that SHEIKH TUSI has considered human truth as the same objective being and the same tangible body, while a prophet’s goal is restricting the performance and duties of the obligated servants. However, Sadr al-Muta’allehin, with his philosophical view, has considered the truth of a tame human being is a combination of soul and body. He has regarded the evolution of the soul for reaching human truth as the purpose of the existence of a prophet. The necessity of the prophet is atomically clarified by his explanation of human truth. Regarding the methodological difference between these two thinkers, it should be said that the Mulla Sadra’s reason for the necessity of prophecy is clearer than that of SHEIKH TUSI although both of them have apparently explained this issue with their rational methods. The difference in their methods becomes clear by reflecting on the rationalism of each of them. There is no need for revelation, but its scope is limited to reasoning and argumentation. Mulla Sadra has considered reasoning to be the lowest reason. He has regarded reasoning activity to be possible up to the endless stage of intuition. This philosophical system, along with special attention to quotations and intuitions, is considered comprehensive.

Two ancient Shiite catalogs, the list of SHEIKH TUSI and the list of Najashi, whose authors lived in the city during the heyday of the Baghdad Theological School, provide pure and first-hand information about this school, which can be extracted, categorized and analyzed to give an overview of the theological school of Baghdad. According to Najashi and SHEIKH TUSI, 25 Imami (Shi’a) theologians were identified in Baghdad from the late third to mid-fifth centuries, who wrote 162 theological works on theological topics. Among those works, most of writings were on the topic of Imamate adding up to 50 cases, which can be explained by the status of this topic within the Shi’a beliefs and diverse intellectual atmosphere of Baghdad. Most of these writings have been presented in a monotonous manner with a frequency of 155 cases in terms of the theological writings’ format, and the number of comprehensive theological writings are very few. This difference is also due to the fact that the tradition of theological comprehensiveness was prevalent in the late period of Baghdad (the era of SHEIKH Mufid onwards) and was not known before that.

Famous Shiite jurisprudents consider alimony of wife as a custom, while the traditions and fatwas of the old jurists consider alimony as predetermined. In the history of this jurisprudential issue, the Mabsut of SHEIKH-e TUSI is a turning point in the conversion of predetermined alimony to customary alimony. SHEIKH-e TUSI, the great Shiite jurisprudent, has used Shafi‘i jurisprudence in this development. The effect that SHEIKH-e TUSI has on jurisprudence in this regard is the main issue of this article. This article criticizes the model of SHEIKH-e TUSI in the development of jurisprudence by examining the alimony of the wife in Shiite and Sunni jurisprudential books before the Mabsut and jurisprudential books after the Mabsut.

One of the ways to get to know the history of hadith is to pay close attention to the narrators and key figures in the publication of hadith. The 4th and 5th centuries of the lunar calendar are an outstanding period due to the classification and formation of the Shia Hadith communities and also the stabilization of the position and structure of Imami beliefs. Ibn Walid Qomi is one of these muhaddiths of the fourth century, who directly and indirectly had a great influence on the scholars and muhaddiths of Baghdad. Najashi and SHEIKH TUSI received hundreds of books of the principles of Companions of the Imams with the fixed method and model of Ibn Abi-Jeed from Ibn Walid from Saffar. SHEIKH TUSI uses more books from Ibn Walid's methods and in the meantime he narrates the documents through the intermediary of SHEIKH Saduq or Ibn Walid's son. Ibn Walid's rejali evaluations, where most of his criticisms were made towards some narrators such as Muhammad bin Musa Hamdani or their books, have also been narrated. SHEIKH TUSI has usually accepted or reported these weaknesses without criticism; But Najashi sometimes rejects them and sometimes looks at them with doubt.

The concept of abrogation (naskh) has been one of the most significant and contentious issues in the fields of Quranic interpretation, Quranic sciences, and Islamic jurisprudential principles throughout the history. A review of the existing literature reveals that few studies have been conducted to comprehensively examine the similarities and differences between the perspectives of major scholars on this topic. This study employs a descriptive-analytical method to conduct a comparative analysis of the views of SHEIKH TUSI, presented in the first comprehensive Shia exegesis Al-Tibyān fī Tafsīr al-Quran, and Ayatollah Ma‘rifat, outlined in the first comprehensive collection of Shia Quranic sciences Al-Tamhīd fī 'Ulūm al-Quran. The findings indicate that, while Ayatollah Ma‘rifat aligns with SHEIKH TUSI in most theoretical aspects of abrogation, he diverges in two categories: "abrogation of the text without the ruling" and "abrogation of both the text and the ruling," where he denies the occurrence of abrogation. Moreover, Ayatollah Ma‘rifat introduces innovative classifications, such as "conditional abrogation" and "gradual abrogation," adapting the concept to contemporary socio-temporal contexts. On the exegetical level, despite shared views on the abrogation of certain verses, Ayatollah Ma‘rifat disagrees with SHEIKH TUSI regarding verses such as 2:240 and 2:109 of Surah Al-Baqarah, rejecting their abrogation. This study emphasizes the importance of revisiting the concept of abrogation to better articulate the relationships among Quranic rulings.

The fifth century in the history of compiling the principles of Sunni jurisprudence is the era of the formation of comprehensive works based on different schools of thought. One of the important features of this group of compilations is the citation of the fundamental opinions of the scholars of the previous centuries such as Abu Ali Jobbayi, his son Abu Hashem, Abu Abdollah Basri, and Ghazi Abd al-Jabbar, whose books have not reached us, and therefore, there is no other way to know their opinions except to study the fundamental books written in later centuries, especially the fifth century. This century is also considered a turning point in Twelver Shiism. It was the time when the principles of jurisprudence were compiled in an inclusive and comprehensive form, in which there are many citations of Sunni fundamentalists, which can, along with other Sunni sources, be considered as a source for knowing the sayings of Sunni elders, especially those whose writings became impossible to access in later centuries. In this article, by choosing the book "Al-Oddah fi Osul al-Feghh" by SHEIKH TUSI, written in the fifth century, and by examining some of the topics of the book, which contain the opinions of Sunni fundamentalists, we have tried to determine the position of the book and the opinions expressed in it from the aforementioned perspective.