"Then sit down in a quiet cell, in a corner by yourself, and do what I tell you. Close the door, and withdraw your intellect from everything worthless and transient. Rest your beard on your chest, and focus your physical gaze, together with the whole of your intellect, upon the centre of your belly or your navel. Restrain the drawing-in of breath through your nostrils, so as not to breathe easily, and search inside yourself with your intellect so as to find the place of the heart, where all the powers of the soul reside. To start with you will find there darkness and an impenetrable density. Later, when you persist and practise this task day and night, you will find, as though miraculously, an unceasing joy. For as soon as the intellect attains the place of the heart, at once it sees things of which it previously knew nothing. It sees the open space within the heart and it beholds itself entirely luminous and full of discrimination."