سورة Al-Imran ( The Famiy of Imran ) - الآية 154

Then He sent down upon you, after grief, security -- a slumber overcoming a party of you; and a party themselves had grieved, thinking of God thoughts that were not true such as the pagans thought, saying, 'Have we any part whatever in the affair?' Say: 'The affair belongs to God entirely.' They were concealing in their hearts that they show not to thee, saying, 'Ah, if we had had a part in the affair, never would we have been slain here.' Say: 'Even if you had been in your houses, those for whom slaying was appointed would have sallied forth unto their last couches'; and that God might try what was in your breasts, and that He might prove what was in your hearts; and God knows the thoughts in the breasts.