(Muhammad) 47 : 20
وَيَقُولُ الَّذِينَ آمَنُوا لَوْلَا نُزِّلَتْ سُورَةٌ ۖ فَإِذَا أُنْزِلَتْ سُورَةٌ مُحْكَمَةٌ وَذُكِرَ فِيهَا الْقِتَالُ ۙ رَأَيْتَ الَّذِينَ فِي قُلُوبِهِمْ مَرَضٌ يَنْظُرُونَ إِلَيْكَ نَظَرَ الْمَغْشِيِّ عَلَيْهِ مِنَ الْمَوْتِ ۖ فَأَوْلَىٰ لَهُمْ
And those who believed say, “Why is not a Surath sent down?” Thus, when a decisive Surah is sent down, and fighting is mentioned in it, you see those in whose hearts is disease looking at you with the look of one fainting from death; then it is most suitable for them.
Battles and Trials occur by the Will of Allah to distinguish the believers from the hypocrites. Believers live with the aim of life learned from Adhikr and entrust all matters to Allah, whereas hypocrites forget Allah and prefer bodily and worldly life. When called to battle, they react as if they were being called to death, showing fear and panic. Such people lose both this world and the Hereafter. See explanation 4: 77-79; 9: 64-65; and 33: 12-13, 19.