This is because Allah has revealed the Book with the truth; and surely those who go against the Book are in a great opposition.

(All) people are a single nation; so Allah raised prophets as bearers of good news and as warners, and He revealed with them the Book with truth, that it might judge between people in that in which they differed; and none but the very people who were given it differed about it after clear arguments had come to them, revolting among themselves; so Allah has guided by His will those who believe to the truth about which they differed and Allah guides whom He pleases to the right path.

Then after sorrow He sent down security upon you, a calm coming upon a party of you, and (there was) another party whom their own souls had rendered anxious; they entertained about Allah thoughts of ignorance quite unjustly, saying: We have no hand in the affair. Say: Surely the affair is wholly (in the hands) of Allah. They conceal within their souls what they would not reveal to you. They say: Had we any hand in the affair, we would not have been slain here. Say: Had you remained in your houses, those for whom slaughter was ordained would certainly have gone forth to the places where they would be slain, and that Allah might test what was in your breasts and that He might purge what was in your hearts; and Allah knows what is in the breasts.

They said: O our people! we have listened to a Book revealed after Musa verifying that which is before it, guiding to the truth and to a right path: