The story masterfully illustrates the difference between two divine epistemologies: 'Ilm al-Shari'ah (Legislative Knowledge) and 'Ilm al-Ladunni (Directly-Bestowed Knowledge). Moses, the master of Shari'ah, judges based on observable actions, which is correct for societal law. Al-Khidr operates from 'Ilm al-Ladunni, which sees the underlying reality and divine purpose. This teaches that an action can be outwardly prohibited by the law but inwardly commanded by divine wisdom for a specific, hidden purpose. Al-Khidr's final statement, 'I did not do it of my own accord' (18:82), confirms his actions were by divine command, not personal whim, thus reconciling the two knowledge streams under the single authority of Allah.

— Ibn Kathir, Al-Qurtubi

The entire journey is a divine lesson in humility for Moses and, by extension, all seekers of knowledge. A hadith explains the journey's context: Moses was asked, 'Who is the most learned of people?' and he replied, 'I am.' Allah then revealed to him, 'There is a servant of Ours at the junction of the two seas who is more learned than you.' The entire arduous journey and the subsequent challenging lessons were orchestrated by Allah to teach one of His greatest prophets that no matter how much knowledge one possesses, one must never claim to have encompassed it all. The fish coming back to life was the sign—a miracle that defied Moses's understanding of natural laws, preparing him for a teacher whose actions would also defy his understanding of religious law.

— Sahih al-Bukhari, Ibn Hajar al-Asqalani