Read Page 72 of the Quran

وَمَآ أَصَـٰبَكُمْ يَوْمَ ٱلْتَقَى ٱلْجَمْعَانِ فَبِإِذْنِ ٱللَّهِ وَلِيَعْلَمَ ٱلْمُؤْمِنِينَ ﴿166﴾

And what struck you on the day the two armies met was by permission of Allah that He might make evident the [true] believers.

وَلِيَعْلَمَ ٱلَّذِينَ نَافَقُوا۟ ۚ وَقِيلَ لَهُمْ تَعَالَوْا۟ قَـٰتِلُوا۟ فِى سَبِيلِ ٱللَّهِ أَوِ ٱدْفَعُوا۟ ۖ قَالُوا۟ لَوْ نَعْلَمُ قِتَالًۭا لَّٱتَّبَعْنَـٰكُمْ ۗ هُمْ لِلْكُفْرِ يَوْمَئِذٍ أَقْرَبُ مِنْهُمْ لِلْإِيمَـٰنِ ۚ يَقُولُونَ بِأَفْوَٰهِهِم مَّا لَيْسَ فِى قُلُوبِهِمْ ۗ وَٱللَّهُ أَعْلَمُ بِمَا يَكْتُمُونَ ﴿167﴾

And that He might make evident those who are hypocrites. For it was said to them, "Come, fight in the way of Allah or [at least] defend." They said, "If we had known [there would be] fighting, we would have followed you." They were nearer to disbelief that day than to faith, saying with their mouths what was not in their hearts. And Allah is most Knowing of what they conceal -

ٱلَّذِينَ قَالُوا۟ لِإِخْوَٰنِهِمْ وَقَعَدُوا۟ لَوْ أَطَاعُونَا مَا قُتِلُوا۟ ۗ قُلْ فَٱدْرَءُوا۟ عَنْ أَنفُسِكُمُ ٱلْمَوْتَ إِن كُنتُمْ صَـٰدِقِينَ ﴿168﴾

Those who said about their brothers while sitting [at home], "If they had obeyed us, they would not have been killed." Say, "Then prevent death from yourselves, if you should be truthful."

وَلَا تَحْسَبَنَّ ٱلَّذِينَ قُتِلُوا۟ فِى سَبِيلِ ٱللَّهِ أَمْوَٰتًۢا ۚ بَلْ أَحْيَآءٌ عِندَ رَبِّهِمْ يُرْزَقُونَ ﴿169﴾

And never think of those who have been killed in the cause of Allah as dead. Rather, they are alive with their Lord, receiving provision,

فَرِحِينَ بِمَآ ءَاتَىٰهُمُ ٱللَّهُ مِن فَضْلِهِۦ وَيَسْتَبْشِرُونَ بِٱلَّذِينَ لَمْ يَلْحَقُوا۟ بِهِم مِّنْ خَلْفِهِمْ أَلَّا خَوْفٌ عَلَيْهِمْ وَلَا هُمْ يَحْزَنُونَ ﴿170﴾

Rejoicing in what Allah has bestowed upon them of His bounty, and they receive good tidings about those [to be martyred] after them who have not yet joined them - that there will be no fear concerning them, nor will they grieve.

۞ يَسْتَبْشِرُونَ بِنِعْمَةٍۢ مِّنَ ٱللَّهِ وَفَضْلٍۢ وَأَنَّ ٱللَّهَ لَا يُضِيعُ أَجْرَ ٱلْمُؤْمِنِينَ ﴿171﴾

They receive good tidings of favor from Allah and bounty and [of the fact] that Allah does not allow the reward of believers to be lost -

ٱلَّذِينَ ٱسْتَجَابُوا۟ لِلَّهِ وَٱلرَّسُولِ مِنۢ بَعْدِ مَآ أَصَابَهُمُ ٱلْقَرْحُ ۚ لِلَّذِينَ أَحْسَنُوا۟ مِنْهُمْ وَٱتَّقَوْا۟ أَجْرٌ عَظِيمٌ ﴿172﴾

Those [believers] who responded to Allah and the Messenger after injury had struck them. For those who did good among them and feared Allah is a great reward -

ٱلَّذِينَ قَالَ لَهُمُ ٱلنَّاسُ إِنَّ ٱلنَّاسَ قَدْ جَمَعُوا۟ لَكُمْ فَٱخْشَوْهُمْ فَزَادَهُمْ إِيمَـٰنًۭا وَقَالُوا۟ حَسْبُنَا ٱللَّهُ وَنِعْمَ ٱلْوَكِيلُ ﴿173﴾

Those to whom hypocrites said, "Indeed, the people have gathered against you, so fear them." But it [merely] increased them in faith, and they said, "Sufficient for us is Allah, and [He is] the best Disposer of affairs."