Surah An-Nisa 4:104

وَلَا تَهِنُوا۟ فِى ٱبْتِغَآءِ ٱلْقَوْمِ ۖ إِن تَكُونُوا۟ تَأْلَمُونَ فَإِنَّهُمْ يَأْلَمُونَ كَمَا تَأْلَمُونَ ۖ وَتَرْجُونَ مِنَ ٱللَّهِ مَا لَا يَرْجُونَ ۗ وَكَانَ ٱللَّهُ عَلِيمًا حَكِيمًا

And do not weaken in pursuit of the enemy. If you should be suffering - so are they suffering as you are suffering, but you expect from Allāh that which they expect not. And Allāh is ever Knowing and Wise.

Translation: Saheeh International

Tafsir

After they returned from Uhud the Prophet s dispatched a group to seek out Abū Sufyān and his companions but they complained about their wounds and the following was revealed Be not faint be not weak in seeking in pursuing the enemy the disbelievers in order to fight them; …

Excerpt from Tafsir al-Jalalayn, commentary on 4:104, via Quran.com. The reader has the full commentary and 9 more tafsirs.