The word Imam al-Mubin occurred twice in the Koran (36:12 and 15:79). The word Imam (pl. a'imma) means a model, an exemplar, a teacher, a guide or a path. The word mubin means manifest, apparent, present, or visible. Besides, the word mubin has a special significance. In Arabic, mubin and the root b-y-n means readily apparent. Thus, Imam al-Mubin means manifest or apparent Imam.

The Christian Crusaders and their occidental chroniclers were completely ignorant of Islam. They knew Islam through the literature of the Sunnis, and translated the Koran in the same vein. Peter de Venerable (1094-1156) was Abbot of Cluny in Toledo. The circle of scholars he had commissioned produced mutilated translation of the Koran for the first time from Arabic into Latin. Peter de Cluny (d. 551/1156) and Robert of Ketton also produced the Latin translation of the Koran in 538/1143, and it was followed by the translation of Mark of Toledo (1190-1200) under the title of Alcorani Machomati Liber. Joinville and Pedro de Alfonso and other also followed them in the 12th century. Since the European scholars were yet unknown with the Shi'ite Islam, they like the Sunnis translated the meaning of the Imam in a wrong sense, and the practice is still continued. Hence, the Imam al-Mubin is translated as Codex clear (Richard Bell), Clear Register (A.J. Arberry), Open Book (John Naish), Clear Model or Clear Prototype (T.P. Hughes), Clear Book (J.M. Rodwell, Margoliouth), Plain Register (George Sale), Plain Model (E.H. Palmer), Claro Registo (Bento de Castro), etc.

The Sunni scholars for the most part render its meaning as lauh mahfuz or Clear Book. The word mahfuz means that which is guarded or concealed, as it is said hafizs sirr means he concealed. It contradicts the meaning of Imam al-Mubin as the word mubin means open, manifest or apparent; which is opposite to the meaning of mahfuz. The word Imam al-Mubin is also used in the Koran (15:79): "Verily both (Shuaib and Saleh) are on an apparent path (Imam al-Mubin) (15:79). If Imam al-Mubin means lauh mahfuz, then it will mean that both prophets were in or on the lauh mahfuz!??

The Sunnis also make its meaning as Clear Book being the title of the Koran. Suyuti gave fifty-five different titles of the Koran in al-Itaqan, in which the title of Koran as Imam al-Mubin is not found. God says, "And of everything We have created pairs that you may be mindful" (51:49), and according to Hadith al-Saqlain, the Imam is the pair of the Koran, which is tied together and will not be separated till the day of judgment. Thus, God says (36:12) for the Imam: "And We have vested everything in the Imam al-Mubin" (wa kulla shayin ahsaynahu fi imamim mubin), and almost in the equal strain for the Koran (78:29): "And We have vested everything in the Book" (wa kulla shayin ahsaynahu kitaba). Thus, the making of Imam al-Mubin as the Koran is an irrational theory.

The institution of the Imamate is a cornerstone among the Shi'ites. The Sunnis have no basic idea of the Shi'ite concept of Imamate, and evidently they will mean the Koranic term Imam al-Mubin in different notions. According to the Shi'ites, the Imam al-Mubin means Manifest Imam or Apparent Imam. When the above Koranic verse (36:12) revealed, Abu Bakr and Umar asked, "Does Imam al-Mubin mean the Torah?" The Prophet said, "No." When it was asked, "Does it mean the Gospel?" The Prophet replied in negative. It was again questioned, "Does it mean the Koran?" The Prophet said, "No." Meanwhile, Ali bin Abu Talib came, the Prophet said, "Lo! He is the Imam al-Mubin. God has accommodated everything in him." (Dhur-e-Manthur, 5:261).

Ammar bin Yasir relates that once Ali bin Abu Talib said, "I am the Imam al-Mubin. I can explicitly distinguish between truth and untruth, and I have inherited this status from the Prophet" (Tafsir al-Safi, p. 461). The Prophet also said, "There is no knowledge that my Lord has not taught me, and that I have not taught Ali. Whatever knowledge God has taught me, I have vested it within Ali" (Tafsir al-Muttaqin, p. 528).

Ammar bin Yasir relates: Once I passed through a valley with Ali bin Abu Talib, where we saw a tremendous heap of the ants. I asked, "Is there any one who can count these ants?" Ali said, "Verily, I can show a person who can count them and knows even their genders." I asked, "Who is that person?" Ali said, "Did you not read the chapter of Yasin in the Koran, containing the verse: