Then, after grief, He sent down security for you. As slumber did it overcome a party of you, while (the other) party, who were anxious on their own account, thought wrongly of Allah, the thought of ignorance. They said: Have we any part in the cause? Say (O Muhammad): The cause belongeth wholly to Allah. They hide within themselves (a thought) which they reveal not unto thee, saying: Had we had any part in the cause we should not have been slain here. Say: Even though ye had been in your houses, those appointed to be slain would have gone forth to the places where they were to lie. (All this hath been) in order that Allah might try what is in your breasts and prove what is in your hearts. Allah is Aware of what is hidden in the breasts (of men).