Al-Baqarah - 2:12

أَلَآ إِنَّهُمْ هُمُ ٱلْمُفْسِدُونَ وَلَـٰكِن لَّا يَشْعُرُونَ

Unquestionably, it is they who are the corrupters, but they perceive [it] not.