Surah Al-Ma'idah 5:79

كَانُوا۟ لَا يَتَنَاهَوْنَ عَن مُّنكَرٍ فَعَلُوهُ ۚ لَبِئْسَ مَا كَانُوا۟ يَفْعَلُونَ

They used not to prevent one another from wrongdoing that they did. How wretched was that which they were doing.

Translation: Saheeh International

Tafsir

They did not prevent one another that is one would not forbid the other from committing again any indecency that they committed; verily evil was what they used to do verily evil was this deed of theirs.

Excerpt from Tafsir al-Jalalayn, commentary on 5:79, via Quran.com. The reader has the full commentary and 9 more tafsirs.