Word by Word Analysis

وَإِن مِّن شَىْءٍ إِلَّا عِندَنَا خَزَآئِنُهُۥ وَمَا نُنَزِّلُهُۥٓ إِلَّا بِقَدَرٍ مَّعْلُومٍ 21

And there is not a thing but that with Us are its depositories, and We do not send it down except according to a known [i.e., specified] measure.