“The Prophet (may God bless him and grant him peace) said, “The heart of the believer is more unsteady than a cooking pot as it boils. He also said, “The heart of the believer is between two of the fingers of the Merciful.” During such strenuous effort the physical constitution may be disordered, the intellect confused, and the body diseased.
If progress in the discipline and improvement of the soul is not made by means of the realities of the sciences, then the heart is ensnared with corrupt imaginings in which the soul trusts for a long time before they come to an end; and one may live out his appointed time without succeeding.