Qasas versus Hadith

In Qur'an the words *qasas* and *hadith* are at times used in meanings that are close to each other. For example: the use of *qasas* as in story-narration: > We narrate to you, [O Muhammad], the best of **stories** (*qasas*) in what We have > revealed to you of this Qur'an although you were, before it, among the > unaware. **—12:3** versus the use of *hadith* as in story-narration: > Has not there come to you the **story** (*hadith*) of Moses? Following the theory that Allah would never use words randomly, has the scholars explained difference between these two words *when they are used in the above sense*? What is the difference *exactly*?