Allah created mankind from His sheer power and mercy, and for this man is forever indebted. Man is the sum of the parts that Allah has given him: the work of the eye is to see; the work the ear is to hear; the work of the mind is to think, and the work of the heart is to love.
There is no one alive who does not love someone or something. If that love is for the sake of Allah, then it becomes a means to earn reward. However, if that love is purely for the sake of satisfying one's nafs, then it becomes a means for sin and earning Allah's Wrath.
A room is either lit or dark: it cannot be both and it can neither be lit nor dark. In exactly the same way, the heart will be enlightened if it has the love of Allah within it. If devoid of this love, it will surely be dark because of the love of creation. It is said that the heart cannot be at peace unless it is in love, whether that is with a person or thing.