Surah Al-Anfal 8:12

إِذْ يُوحِى رَبُّكَ إِلَى ٱلْمَلَـٰٓئِكَةِ أَنِّى مَعَكُمْ فَثَبِّتُوا۟ ٱلَّذِينَ ءَامَنُوا۟ ۚ سَأُلْقِى فِى قُلُوبِ ٱلَّذِينَ كَفَرُوا۟ ٱلرُّعْبَ فَٱضْرِبُوا۟ فَوْقَ ٱلْأَعْنَاقِ وَٱضْرِبُوا۟ مِنْهُمْ كُلَّ بَنَانٍ

[Remember] when your Lord inspired to the angels, "I am with you, so strengthen those who have believed. I will cast terror into the hearts of those who disbelieved, so strike [them] upon the necks and strike from them every fingertip."

Translation: Saheeh International

Tafsir

When your Lord inspired the angels with whom He reinforced the Muslims saying ‘I am with you with assistance and victorious help so make the believers stand firm by helping them and giving them good tidings. I shall cast terror fear into the hearts of the disbelievers; …

Excerpt from Tafsir al-Jalalayn, commentary on 8:12, via Quran.com. The reader has the full commentary and 9 more tafsirs.