The use of “lan” rather than “lā” for negation.

According to our teacher ʿAllāmah Ṭabāṭabāʾī, the act of patience (ṣabr) is dependent on capability, and in the verse, the act is negated through the negation of one of its causes: “lan tastaṭīʿ.” Then the negation of patience comes through negating the cause of capability, which is comprehension of the matter and knowledge of the actual reality and its explanation (taʾwīl), so that one would know how to proceed accordingly. God Almighty negated Moses’s patience regarding the manifestations of Khiḍr’s knowledge of events when He said: “lan tastaṭīʿ maʿī,” but He did not negate Moses’s patience regarding Khiḍr’s knowledge itself, and did not say “you will not have patience for what I know and cannot bear it.” When Khiḍr informed Moses about the explanation of the events, he showed no reaction; rather, his reactions came when he witnessed the events themselves during the course of instruction. Thus, knowledge has one ruling and its manifestations have another.(174)

This story is similar to the story of Moses when he returned from the appointed time to his people and encountered their calf-worship, becoming intensely angry. Prior to this, God had informed Moses about this matter during the appointed time and he showed no reaction, even though God’s word is truer than sensory observation.(175) This story is narrated in Sūrah al-Aʿrāf.(176) Thus the verse “Indeed, you will never be able to have patience with me” until its end, indicates that Moses could not endure the teaching method that Khiḍr had adopted for his instruction, not that he could not bear the knowledge itself.(177)