CHAPTER ONE Concerning the Ailments of the Hearts and their Cures

Indeed all praise is due to Allah, we seek His help, and we seek His forgiveness, and we seek refuge in Allah from the evil of our souls and the evil of our actions. Whomsoever Allah guides, none can misguide, and whomsoever Allah misguides, none can guide.

I bear witness that there is no deity worthy of worship except for Allah, the One Who has no partner, and I bear witness that Muhammad is His servant and Messenger.

Allah the Exalted said about the hypocrites,
In their hearts is a disease and Allah has increased their disease. [Surah al-Baqarah (2) : 10]

That He may make what is thrown in by Satan a trial for those in whose hearts is a disease and whose hearts are hardened. [Surah al-Hajj (22) : 53]

If the hypocrites, and those in whose hearts is a disease, and those who spread false news among the people of Madinah cease not, We shall certainly let you overpower them, then they will not be able to stay in it as your neighbours but for a little while. [Surah al-Ah^ab (33) : 60]

…and that no doubts may be left for the People of the Book and the believers, and that those in whose hearts is a disease and the disbelievers may say, ‘What does Allah intend by this parable?’ [Surah al-Muddaththir (74) : 31]

…There has come to you good advice from your Lord, and a healing for that which is in the hearts, a guidance and a mercy for the believers. 

سقطمنالنسخة

…and heal the breast of a believing people and removes the anger of their hearts… [Surah Tawbah (9) : 14-15]

The disease of the body is the opposite of its being sound and in good health, it is a degeneration that occurs in it causing a failure of the natural senses of perception and movement. So with respect to its perception either it goes completely such as blindness or deafness, or it perceives objects incorrectly – such as its perceiving something sweet to be bitter or its hallucinating things that have no reality in the real world.

With respect to the failure of its movements then examples of this would be the inability to digest food, or the body’s aversion to nourishment that it is need of, or its desire of things that would weaken it, leading to illnesses as a result of these but not leading to death or physical ruin.