"And the Messenger will say, 'O my Lord, indeed my people,'" meaning: those who did not believe in him, "have taken this Quran as a thing to be abandoned." Mujahid's interpretation is: he says, they speak nonsense (yahjurun) regarding it.
Muhammad says: The meaning of Mujahid's statement is that they placed it in the position of 'hajr'. And 'hajr' is delirious talk and speech that is of no benefit; it is said: 'So-and-so is talking nonsense (yahjuru) in his sleep,' meaning: he is delirious.