أَلَآ
Beware
إِنَّهُمْ
indeed they
هُمُ
themselves
ٱلْمُفْسِدُونَ
[are] the ones who spread corruption
وَلَـٰكِن
[and] but
لَّا
not
يَشْعُرُونَ
they realize (it)
أَلَآ إِنَّهُمْ هُمُ ٱلْمُفْسِدُونَ وَلَـٰكِن لَّا يَشْعُرُونَ
Indeed, it is they who are the corruptors, but they fail to perceive it.