Surah Muhammad 47:4

فَإِذَا لَقِيتُمُ ٱلَّذِينَ كَفَرُوا۟ فَضَرْبَ ٱلرِّقَابِ حَتَّىٰٓ إِذَآ أَثْخَنتُمُوهُمْ فَشُدُّوا۟ ٱلْوَثَاقَ فَإِمَّا مَنًّۢا بَعْدُ وَإِمَّا فِدَآءً حَتَّىٰ تَضَعَ ٱلْحَرْبُ أَوْزَارَهَا ۚ ذَٰلِكَ وَلَوْ يَشَآءُ ٱللَّهُ لَٱنتَصَرَ مِنْهُمْ وَلَـٰكِن لِّيَبْلُوَا۟ بَعْضَكُم بِبَعْضٍ ۗ وَٱلَّذِينَ قُتِلُوا۟ فِى سَبِيلِ ٱللَّهِ فَلَن يُضِلَّ أَعْمَـٰلَهُمْ

So when you meet those who disbelieve [in battle], strike [their] necks until, when you have inflicted slaughter upon them, then secure [their] bonds, and either [confer] favor afterwards or ransom [them] until the war lays down its burdens. That [is the command]. And if Allāh had willed, He could have taken vengeance upon them [Himself], but [He ordered armed struggle] to test some of you by means of others. And those who are killed in the cause of Allāh - never will He waste their deeds.

Translation: Saheeh International

Tafsir

So when you encounter in battle those who disbelieve then attack them with a striking of the necks fa-darba’l-riqābi is a verbal noun in place of the full verbal construction that is to say fa’dribū riqābahum ‘then strike their necks’ in other words slay them — reference is made to the ‘striking of the necks’ because …

Excerpt from Tafsir al-Jalalayn, commentary on 47:4, via Quran.com. The reader has the full commentary and 9 more tafsirs.