ذَلِكَ بِأَنَّهُمْ شَاقُّوا اللَّهَ وَرَسُولَهُ وَمَنْ يُشَاقِقِ اللَّهَ وَرَسُولَهُ فَإِنَّ اللَّهَ شَدِيدُ الْعِقَابِ ﴿۱۳﴾ ذَلِكُمْ فَذُوقُوهُ وَأَنَّ لِلْكَافِرِينَ عَذَابَ النَّارِ ﴿۱۴﴾ يَا أَيُّهَا الَّذِينَ آمَنُوا إِذَا لَقِيتُمُ الَّذِينَ كَفَرُوا زَحْفًا فَلَا تُوَلُّوهُمُ الْأَدْبَارَ ﴿۱۵﴾ وَمَنْ يُوَلِّهِمْ يَوْمَئِذٍ دُبُرَهُ إِلَّا مُتَحَرِّفًا لِقِتَالٍ أَوْ مُتَحَيِّزًا إِلَى فِئَةٍ فَقَدْ بَاءَ بِغَضَبٍ مِنَ اللَّهِ وَمَأْوَاهُ جَهَنَّمُ وَبِئْسَ الْمَصِيرُ ﴿۱۶﴾

﴾13﴿ Zaalika bi annahum shaaaqqul laaha wa Rasoolah; wa mai yushaqiqil laaha wa Rasoolahoo fa innal laaha shadeedul 'iqaab
﴾14﴿ Zaalikum fazooqoohu wa anna lilkaafireena 'azaaban Naar
﴾15﴿ Yaaa aiyuhal lazeena aamanoo izaa laqeetumul lazeena kafaroo zahfan falaa tuwalloohumul adbaar
﴾16﴿ Wa mai yuwallihim yawma'izin duburahooo illaa mutaharrifal liqitaalin aw mutahaiyizan ilaa fi'atin faqad baaa'a bighadabim minal laahi wa ma'waahu Jahannamu wa bi'sal maseer

﴾13﴿ That is because they opposed Allah and His Messenger. And whoever opposes Allah and His Messenger—then surely Allah is severe in punishment.
﴾14﴿ This is your punishment, so taste it (in this world), and know that for the disbelievers is the punishment of the Fire.
﴾15﴿ O believers! When you meet the disbelievers in battle, do not turn your backs to them.
﴾16﴿ And whoever turns his back to them on that day—except for tactical maneuvering or joining another group—has certainly drawn upon himself the wrath of Allah. And his refuge is Hell, and what an evil destination it is!

[13] In this verse, the reason for the killing of the disbelievers is mentioned, and that reason is “shiqāq” (discord/opposition). Shiqāq originally refers to when something is split into two parts, and one side stands in opposition to the other.
The scholars have written that every polytheist (mushrik) and innovator (mubtadi‘) is in shiqāq with Allah the Exalted and His Messenger, because in opposing them, they have fabricated their own version of religion.
[14] This address is directed to the disbelievers, and it alludes to their killing, captivity, and humiliation at Badr.
"Fa-dhuquhu" (So taste it): This is mentioned in a mocking tone, because the word “taste” is usually used for sweet and pleasant things.
Also, before "wa-anna", the phrase "wa‘lamu" (know) is implied but not explicitly mentioned.
[15] This is the first law for the warriors: Do not flee from the battlefield, and such fleeing is considered a major sin.
The word "adbar" (backs) indicates the ugliness and disgrace of the act—turning one’s back in battle.
"Zahfan" originally refers to the crawling of an infant, meaning the army advances slowly due to its large size. It also refers to approaching—indicating the moment during battle when the armies draw near to each other.
[16] In this verse, the punishment of the Hereafter is mentioned for those who flee the battlefield. However, two situations are exempted from this ruling:
1. Tactical maneuvering: when a person turns his back on the enemy as a strategy—so that he can suddenly return and attack.
2. Seeking reinforcement: when someone has been separated from his group and turns back to join them or another group to receive support.
In both of these cases, there is turning away, but not with the intention of fleeing.