Blind Hearts

Ibn Taymiyyah (rahimahUllaah) stated:

"Just as the person who closes his eyes doesn't see anything even if he isn't blind, likewise the case of the heart in relation to the stain of sins which blind the heart so that it doesn't see the truth. This is the case even if the heart is not blind, like the blindness of the disbeliever."

Source: Al-Eemaan By Shaykhul Islaam Ibn Taymiyyah