To other organs, the heart is like a king in charge of his soldiers; they are subservient to him and his desires, and are guided or misled by him, as they follow him in all that he resolves to do or avoids. That is why the Prophet, , said: “Beware! There is a piece of flesh in the body; if it is sound, the whole body is reformed, but if it is corrupt, the whole body is spoilt. Verily, it is the heart.” [Al-Bukhari and Muslim]

　　Hence, the heart is the king of the body, which executes all that it commands and takes its lead. The limbs are unable to do anything unless this particular organ wants and intends to. Since the heart reigns supreme, and is responsible for its wards, as is every guardian, it is essential that the righteous person prioritizes paying close attention to it and making it sound and upright. Further, investigating the diseases of the heart and their cures is the first thing sincere worshippers should undertake.

　　When Satan, the enemy of Allah, realized that everything revolved around, and depended on, the heart, he began to whisper into it, expose it to temptations and adorn to it every condition and deed that strays us from the way of Allah The Almighty. He also accompanied that with incentives to follow what prevents the heart from the causes of success.

　　Furthermore, Satan set various snares such that if they do not entrap the heart, it will at least be hindered by them. Therefore, a person cannot escape his plots and traps, except by continuously seeking help from Allah The Almighty against him, acting in a manner that necessitates His Pleasure and by sincerely turning to Him at times of stillness and activity. Also essential is humiliating one’s self to Him in worship, so as to guarantee being included among those Allah The Almighty mentions, when He Says (what means): {Indeed, My servants - no authority will you have over them} [Quran 15:42].

　　Categories of hearts

　　The heart is generally described as either alive or dead, but it can be divided into three types: sound, dead and sick.

　　· The sick heart: this heart is alive, but contains some flaws, so it is made up of two different parts, each of which is instrumental, but only the dominating one is followed. Such a heart demonstrates love for Allah The Almighty, faith in Him, sincerity to Him and reliance on Him, which constitute the essence of its life. However, it also has a love and preference for desires, and displays a keenness for them; it bears envy, haughtiness, ostentation, love of domination and corruption on Earth – all of which constitute the material of its ruin and destruction.

　　Such a heart is tested, torn between two callers: one that invites it to Allah The Almighty, His Messenger and the Hereafter, and another that calls it to this worldly life. The positive response of this kind of heart is to the most convenient and nearer of the two.

　　In conclusion, the first category of hearts is alive and humble, while the second is hard and dead. The third category, though, is sick and may equally be close to either safety or destruction.