[Remember how it was] when He caused inner calm to enfold you, as an assurance from Him, and sent down upon you water from the skies, so that He might purify you thereby and free you from Satan's unclean whisperings and strengthen your hearts and thus make firm your steps. 11 And when Allah revealed to the angels, saying: 'I shall be with you. Give courage to the believers. I shall cast terror into the hearts of the unbelievers. Strike them above the necks, smite their finger tips' 12 That was because they defied God and His Messenger. He who defies God and His Messenger shall be severely punished by God. 13 That (is the award), so taste it, and (know) that for disbelievers is the torment of the Fire. 14 Believers, when you encounter unbelievers on the march do not turn your backs to them in flight. 15 For any one who turns his back on that day, except to manoeuvre or rally to his side, will bring the wrath of God on himself, and have Hell as abode; and what an evil destination! 16 You did not kill them; it was God who killed them; and when you [Prophet] threw [sand] at them it was not you, but God who threw it so that He might confer on the believers a great favour from Himself. Surely, God is all hearing, all-knowing, 17 This is how God causes the (evil) plans of the unbelievers to fail. 18 (Tell the unbelievers:) 'If you have sought a judgement, then surely a judgement has come to you. And if you desist from disobedience, it is all the better for you. But if you revert to your mischief, We will again chastise you; and your host, howsoever numerous, will never be of any avail to you. Know well, Allah is with the believers.' 19