Surah Ash-Shuraa 42:39

وَٱلَّذِينَ إِذَآ أَصَابَهُمُ ٱلْبَغْىُ هُمْ يَنتَصِرُونَ

And those who, when tyranny strikes them, they retaliate [in a just manner].

Translation: Saheeh International

Tafsir

and those who when they suffer aggression injustice defend themselves — these are another category — that is to say they retaliate against those who wrong them in the same manner in which the latter wronged them as God exalted be He says

Excerpt from Tafsir al-Jalalayn, commentary on 42:39, via Quran.com. The reader has the full commentary and 9 more tafsirs.