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.