Ibn Qayyim Al Jawziyyah:
The similitude of the heart in its travel to Allah is like a bird. Love is its head, and khawf and rajaa’ are the wings. When the head and both wings are sound, the bird is capable and skilled in flying. However, when the head is cut off, the bird will die. When the bird loses a wing, it then becomes a target for every hunter and predator. The scholars favored, however, the wing of khawf over the wing of rajaa’, especially when the person is young and healthy. They favored the wing of rajaa’ over the wing of khawf when the person is about to leave this world.
The soul is a temptress and loves to look at beautiful forms and the eye is the guide of the heart. The heart commissions its guide to go and look to see what is there and when the eye informs it of a beautiful image it shudders out of love and desire for it.