Thus, a servant’s share (1) in an open heart is proportionate to his share of this light. The same applies to physical light and darkness: light opens (2) the heart, while darkness constricts it.
Another cause is knowledge, for it (3) opens the heart and expands it until it becomes wider than the world. Ignorance, by contrast, leaves it constricted, confined, and imprisoned. The more a servant’s knowledge grows, the more his heart opens and expands. This does not apply to every kind of knowledge, but rather to the knowledge inherited from the Messenger (may Allah bless him and grant him peace), which is beneficial knowledge. Those who possess it have the most open hearts (4), the greatest breadth of heart, the finest character, and the most pleasant lives.
Another cause is turning to Allah, loving Him wholeheartedly, devoting oneself to Him, and finding delight in worshipping Him. Nothing opens a servant’s heart more than this, to the point that he sometimes says: “If my state in Paradise is like this, then I shall indeed be living a pleasant life.” Love has a remarkable effect in opening the heart, bringing contentment to the soul, and filling the heart with bliss—an effect known only to those who have experienced it. The stronger and more intense this love becomes, the more spacious and open the heart grows. It becomes constricted only at the sight of idle people devoid of such devotion: seeing them is like grit in his eye, and keeping their company is a fever in his soul.
Among the greatest causes of a constricted heart are turning away from Allah, attaching the heart to others besides Him, neglecting His remembrance, and loving other than Him. Whoever loves anything other than Allah is tormented by it, and his heart is imprisoned in that love. No one on earth is more wretched, more downcast, more troubled in life, or more weary of heart.