reasonable. On the other hand, human intellect is a necessary means of his evolution, but is not sufficient. Imperfection of human intellect is evidenced in constant controversies over economic, ethical, family and other issues in his life etc. that have resulted in conflicting philosophies. Based on these contemplations, a sound mind rules that consistent with Divine wisdom, leaders and teachers have to be inspired to teach humans the correct way of life. In view of the Quran The following reasons have been mentioned in the Quran for Divine appointment of prophets: Strengthening the foundations of Tawhid (the oneness [of God]) and fight against any deviation as in sura An-Nahl, verse 36: "And We certainly sent into every nation a messenger, [saying], "Worship Allah and avoid Taghut." And among them were those whom Allah guided, and among them were those upon whom error was [deservedly] decreed. So proceed through the earth and observe how was the end of the deniers". On the purpose of Prophethood, Ali ibn Abi Talib, the first Shia Imam and cousin and son-in-law of Muhammad, in a sermon during his caliphacy, has said that Allah assigned the prophets mission to teach the servants of God about Tawhid and attributes of God. To acquaint people with the divine teachings and the manner of purification of the soul as in sura Al-Jumua, verse 2: "It is He who has sent among the unlettered a Messenger from themselves reciting to them His verses and purifying them and teaching them the Book and wisdom - although they were before in clear error –" To establish justice in human society, as in sura Al-Hadid verse 25 : "We have already sent Our messengers with clear evidences and sent down with them the Scripture and the balance that the people may maintain [their affairs] in justice". To judge disputes among humans as in sura Al-Baqara, verse 213 :" Mankind was [of] one religion [before their deviation]; then Allah sent the prophets as bringers of good tidings and warners and sent down with them the Scripture in truth to judge between the people concerning that in which they differed. And none differed over the Scripture except those who were given it - after the clear proofs came to them - out of jealous animosity among themselves." As a final ‘hujjah’ (argument, proof, guarantee) for servants of God, as in sura An-Nisa verse 165 :"