This was obligatory for them; it is invalid by necessity of religion and reason. And he did not provide details on the basis of infallibility in the Imam's thought and action, except that we deduce from his sayings that infallibility relates to two aspects he pointed to in his saying: "Agreement is only valid by relying on the affairs of those in authority," which is the infallible Imam from falsehood and injustice. The first aspect is covered by infallibility from falsehood, meaning the opinions, principles, and teachings he calls for and proclaims are all truth and are not mixed with falsehood in any way, such as lying, ignorance, innovation, and other paths leading to error. This is what he confirmed elsewhere, speaking about the Mahdi, saying: "He is infallible in what he calls for of the truth; error is not permissible for him in it." The second aspect is covered by infallibility from injustice. This relates to the governance of people, their affairs, and the management of their matters. The Mahdi affirmed the Imam's infallibility in his actions in this aspect, expressing it as infallibility from corruption, as in his saying: "None upholds the rights of God except justice, the satisfied, infallible from corruption." What is meant by corruption in this context is corruption through committing injustices, practicing oppression and tyranny, and neglecting the interests of the servants. The Mahdi often used the word corruption in this sense, to the point that it became specific to him when used generally. He most often used it in his discussion of the theory. - See other evidence and refutations by other groups in: Ahmad Mahmoud Sobhi, *The Imamate*: 277 onwards, and Al-Baghdadi, *Usul al-Din*: 116. - Ibn Tumart, *Kitab al-Imamah*: 245. - Ibid.: 246. - Ibn Tumart, *Kitab al-Qawa'id*: 257. - Ibn Tumart, *Kitab al-Imamah*: 246.