It was a creedal basis. So he focused his attention on establishing and strengthening this basis, and most of his works were in this regard. We know the following from these works: 1. Al-Murshida: It is a small treatise, not exceeding two pages, containing a brief overview of creedal issues, devoid of proofs. It is perhaps the most widespread of Al-Mahdi's works in the West and the East, as it is considered a summary of his creedal thought. It has been mentioned in many biographical and historical books, and its text has appeared in several places within other works and as a standalone piece. Al-Subki, Ibn Al-Khatib, Al-Barzali, and Al-Nabhani have included it. It appeared standalone in the collection "A'azz ma Yutlab" and in a manuscript collection at the National Library in Tunis (No. 1696). It has been published many times. Some Orientalists took care of translating it. Many scholars explained it, and some commented on it and opposed it.

2. Al-Aqida: It is a treatise on creedal issues, arranged from monotheism to the affirmation of prophethood. It uses rational arguments. It appeared in the collection "A'azz ma Yutlab" and in the list of commentaries under the title "Al-Aqida Al-Kubra," and it is likely the same. (See, for example: Ibn Al-Qunfudh, Al-Farisiyya: 65; Ibn Khaldun, Al-'Ibar: 6/466; Al-Subki, Tabaqat: 5/70; Ibn Al-Khatib, Al-Hulal: 67/87-88; Abu Al-Qasim Al-Barzali, Al-Nawazil: 4/333; Al-Nabhani, Sa'adat Al-Darayn: 69/16-17). Goldziher published it in the journal Majallat (Vol. 44, pp. 168-170), and 'Abd Allah Kunnun in his article "Aqidat Al-Murshida lil-Mahdi ibn Tumart" (Vol. 44, p. 482), and Sa'd Gharab in his article "Al-Murshida ibn Tumart wa Atharuha fi Al-Tafkir Al-Maghribi" (p. 114). Goldziher translated it into German in the journal Majallat (Vol. 44, pp. 170-172), and Henri Massé into French in the memoirs of Henri Massé (p. 105/2). We will provide details about the spread of Al-Murshida, its explanations, and its oppositions later in this research and beyond. See also details in the aforementioned articles by 'Abd Allah Kunnun and Sa'd Gharab.