"And whosoever turns away (blinds himself) from the remembrance of the Most Gracious (Allah) (i.e. this Qur'an and worship of Allah), we appoint for him Shaitan to be a Qarin (an intimate companion) to him. (Qur'an 43:36)
Ibn Qayyim say: "Seek out your heart in three situations:-
1. When you are listening to the Qur'an
2. When you are part of a gathering of remembrance
3. When you are alone and away from the world and it's distractions
If you cannot find your heart in these three situations, then ask Allah to bestow upon you a heart, for indeed you are bereft of one."