In Sura 18 ayahs 59-81, Khidr figures in a mysterious…

““In Sura 18 ayahs 59-81, Khidr figures in a mysterious episode, a thorough study of which would require an exhaustive confrontation with the earliest Quran commentaries. He is represented as Moses' (PBUH) guide, who initiates Moses (PBUH) "into the science of predestination." Thus he reveals himself to be the repository of an inspired divine science, superior to the law (shari'a); thus Khidr is superior to Moses (PBUH) in so far as Moses (PBUH) is a prophet invested with the mission of revealing a shari'a. He reveals to Moses (PBUH) precisely the secret, mystic truth (haqiqa) that transcends the shari'a, and this explains why the spiritually inaugurated by Khidr is free from the servitude of the literal religion. If we consider that Khidr's mission is likewise related o the spiritual mission of the Imam through the identification of Khidr with Elijah (PBUH), it becomes evident that we have here one of the scriptural foundations on which the deepest aspiration of Shi'ism is built. And indeed Khidr's pre-eminence over Moses (PBUH) ceases to be a paradox only if we consider it in this light; otherwise, Moses (PBUH) remains one of the six pre-eminent prophets charged with revealing a shari'a, while Khidr is merely one of the hundred and eighty thousand nabis, mentioned in our traditions.””

— Henry Corbin