Active obstruction of truth

وَهُمْ يَنْهَوْنَ عَنْهُ وَيَنْـَٔوْنَ عَنْهُ ۖ وَإِن يُهْلِكُونَ إِلَّآ أَنفُسَهُمْ وَمَا يَشْعُرُونَ

And they prevent [others] from him and are [themselves] remote from him. And they do not destroy except themselves, but they perceive [it] not.