Then after the setback, He sent down security upon you. Slumber overcame some of you, while others cared only for themselves, thinking of God thoughts that were untrue—thoughts of ignorance—saying, “Is anything up to us?” Say, “Everything is up to God.” They conceal within themselves what they do not reveal to you. And they say, “If it was up to us, none of us would have been killed here.” Say, “Even if you Had stayed in your homes, those destined to be killed would have marched into their death beds.” God thus tests what is in your minds, and purifies what is in your hearts. God knows what the hearts contain.

The Holy Quran · Aal-i-Imraan (The Family of Imraan) · 3:154