For the sake of concision, and to avoid repeating what has already been explained, we will limit ourselves to recalling that in Shī'ism, the question of the Caliphate is eminently transcendental. As such, 'Alī's right to succession cannot, in any way, be subjected to human scrutiny. For Shī'ites, the supreme spiritual status of 'Alī is peerless and cannot be compared to the rank held by other Islāmic leaders. He belongs to a unique and superior spiritual category which was conferred on him by the grace of God.
By bestowing the wilāyah of the Prophet on Alī, God perfected Islām and brought the prophetic mission to a close. The fundamental doctrine of wilāyah is based on the concept of the ta'ālīm of the Imāms. What continues in Islām under the name of wilāyah is, de facto et de iure [by fact and by right], a form of esoteric guidance [al-hidāyah al-bātiniyyah] from which humanity cannot stray without perishing.1
The wilāyah is the guaranteed living embodiment of the spiritual authority of the Prophet which, by the temporal succession of the Twelve Imāms, continues throughout human history until the end of times. Understandably, it is impossible to separate the historical development of Shī'ite Islām from the meta-historical antecedents of wilāyah. 'Alī's Islām cannot be separated from the metaphysical truths which are its telos, its fundamental and final cause. In closing, it is inconceivable to claim that we have dealt with the issue of Imāmate and wilāyah in all of its depth.
We have limited ourselves to addressing the issue of its origins and leaving the topic open to further research. As a result, this study on the origins of Shī'ism must remain incomplete for the time being. In order for it to be complete, it would have been necessary to compile some of the traditions that attest to the extraordinary importance of the secret spiritual life of Shī'ism and the Shī'ite ethos of the Hidden Imām, the seal of the Muhammadan wilāyah, for, as the Prophet has stated, without the continuous living presence of the Imām, neither human beings nor the world can subsist.2
author stated ”[w]hat continues in Islām under the name of wilāyah is, de facto et de iure [by fact and by right], a form or esoteric Prophethood [nubuwwah bātiniyyah].” What the author was attempting to convey was that Shī'ism is the only expression of Islām which, in the words of Corbin, “has preserved and perpetuated the link of divine guidance between man and God through its belief in the Imāmate” unlike Sunnism which “believes that the link between man and God has been severed with the end of the Prophethood” (qtd. Baqr al-Sadr, The Awaited Saviour). As Sayyid Rizvī has pointed out, however, the term “Esoteric Prophethood” for imāmah and wilāyah is problematic as it may lead readers to believe that Shī'ites beliveve in the continuation of nubuwwah. An Imām, after cessation of the Prophethood, still has access to divine guidance through true visions and the voices of angels without actually seeing them [al-muhaddath], as explained in the section of al-Kāfī which describes the Imāms as al-muhaddathun. As per the suggestion of Sayyid Rizvī, the author has opted for the term al-hidāyah al-bātiniyyah which more aptly captures the sense he was attempting to convey
the gate of Allāh, except through which one cannot reach Him, and the path to Him, such that if someone passes along another (path) he will perish, and this is applied to all the Imāms, one after another. Allāh has made them the pillars of the earth. (Kulaynī 88 hadīth 521). It is related in al-Kāfī that Imām al-Sādiq was asked whether the world could exist without there being an Imām in it, to which he responded: “No” (Kulaynī 35: hadīth 447). The Imām is also reported to have said that “Verily, the world can never be without an Imām” (36, hadīth 448), “As long as the world lasts, there will be in it a Proof of Allāh” (36: hadīth 449); “The earth can never last without an Imām who is Allāh's proof for His creatures” (37: hadīth 454). Muhammad al-Bāqir also said that “If the Imām is removed from the earth (even) for an hour (of the day), the earth will surge up with those in it like a sea surges up with those in it” (39: hadīth 458).