(3:139) So do not weaken and do not grieve, and you will be superior if you are [true] believers. (3:140) If a wound should touch you - there has already touched the [opposing] people a wound similar to it. And these days [of varying conditions] We alternate among the people so that Allah may make evident those who believe and [may] take to Himself from among you martyrs - and Allah does not like the wrongdoers - (3:141) And that Allah may purify the believers [through trials] and destroy the disbelievers. (3:142) Or do you think that you will enter Paradise while Allah has not yet made evident those of you who fight in His cause and made evident those who are steadfast? (3:143) And you had certainly wished for martyrdom before you encountered it, and you have [now] seen it [before you] while you were looking on. (3:144) Muhammad is not but a messenger. [Other] messengers have passed on before him. So if he was to die or be killed, would you turn back on your heels [to unbelief]? And he who turns back on his heels will never harm Allah at all; but Allah will reward the grateful. (3:145) And it is not [possible] for one to die except by permission of Allah at a decree determined. And whoever desires the reward of this world - We will give him thereof; and whoever desires the reward of the Hereafter - We will give him thereof. And we will reward the grateful.
