And in the kingdom of this, there were established for him, the Susi, the fundamental principles: Islamic creed, for it is the basis of religion, and the pivot around which all its truths revolve. From it, they derive their strength, and to it, they all return in one way or another. The Holy Quran came to draw attention to this truth, calling for belief in it and acting according to its requirements more than it called attention to the existence of the second. This is because the doctrinal deviation that afflicts creation, afflicts their belief in monotheism more than it afflicts their belief in existence, leading them to polytheism. Secondly, the belief of the Murabitin and the people of Sus in particular did not respond to the truth of correct monotheism. If the scholars and the learned among them believed in the oneness of God according to the apparent meaning of the verses without interpretation, but with delegation, then the common people might have their understanding hardened in this area until anthropomorphism and simile mixed with it. Therefore, the space that monotheism occupied in the thinking of the Mahdi and his movement was a reflection of the status it held in religion, and a reaction to this doctrinal reality in the environment that was the homeland of his call. So he began to declare in his writings and sermons that "Monotheism is the basis of religion upon which it is built," and that its branches are established only after and he kept repeating to his listeners that monotheism is the basis of all religions, it is the religion of the first and the last of the prophets and messengers, and that religion And We did not send any messenger before you except that We revealed to him: "There is no god but I, so worship Me." And he wrote several treatises to explain and detail these meanings, including a treatise on the oneness of the Creator, and a treatise on the fact that monotheism is the basis of religion. The concept of monotheism and its dimensions: Ibn Tumart analyzed and explained the reality of monotheism in its comprehensive concept, and in its theoretical and practical aspects. He summarized this concept in his saying: "Monotheism is the affirmation of the One, and the negation of all else, whether it be a god, a partner, a saint, or a tyrant. Everything worshipped besides Him must be negated." Ibn Tumart, Treatise on (54) That monotheism is the basis of religion: See the same source: (55) 203