One important and old approach taken by Quran researchers is considering the language and how understanding and interpreting of this great text, which enjoys various, religious, epistemological and artistic dimensions, happens. Among such studies are the literary- linguistic approaches to the Quran that people like Sayyid Qutb, Mustansir Mir, Nil Robinson, Toshihiko Izutsu and Angelika Neuwirth have authored works on.
The development of the analysis of different linguistic and semiotic discussions in different texts has made it clear that Quran's text and specially its stories contain many linguistic techniques in conveying and inculcating its exalted concepts which has been touched on by experts less often.   
Analyzing the story of Moses and Khizr in Kahf surah based on analyzing discourse semiotics, this study describes and explains different discourse systems such as eventual, prescriptive and tensional discourse.
In this research we do never intend to know the value of Quranic stories in their having these discourse systems, rather we accept the greatness of Quran in all its dimensions and we pursue to clarify this aspect of discourse systems in its structure and content.In other words, we are going to describe these systems both in the surface and deep structures of this story to depict and prove another valuable aspect of Quranic stories. This research method is content analysis based on semiotic theories that have been raised by people such as Algirdas Julien Greimas and Kurtz in recent years.