In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Imaam Ibnul Qayyim [rahimahullaah] said: There are two types of diseases: Disease of the heart and disease of the body, and both have been mentioned in the Qur’aan. The disease of the heart are two types: [a] The disease of Shubhah [i.e. an affair of falsehood that is made to resemble truth] and Shak [i.e. doubt]. [b] The disease of Shahwah [i.e. evil or vain desires or lewd conduct] and Ghay [i.e. deviation from the right path]. Both of them have been mentioned in the Qur’aan. Allaah [The Most High] stated regarding the disease of Shubhah: [ فِي قُلُوبِهِم مَّرَضٌ فَزَادَهُمُ اللَّهُ مَرَضًا -In their hearts is a disease [of doubt and hypocrisy] and Allah has increased their disease. [2:10]
Allaah [The Most High] said: [وَلِيَقُولَ الَّذِينَ فِي قُلُوبِهِم مَّرَضٌ وَالْكَافِرُونَ مَاذَا أَرَادَ اللَّهُ بِهَٰذَا مَثَلًا ۚ – And that those in whose hearts is a disease [of hypocrisy] and the disbelievers may say: “What Allah intends by this (curious) example?] [74:31]
And Allaah [The Most High] stated about the one who is called to judge by the Qur’aan and the Sunnah, but he refuses and turns away:
وَإِذَا دُعُوا إِلَى اللَّهِ وَرَسُولِهِ لِيَحْكُمَ بَيْنَهُمْ إِذَا فَرِيقٌ مِّنْهُم مُّعْرِضُونَ
وَإِن يَكُن لَّهُمُ الْحَقُّ يَأْتُوا إِلَيْهِ مُذْعِنِينَ
أَفِي قُلُوبِهِم مَّرَضٌ أَمِ ارْتَابُوا أَمْ يَخَافُونَ أَن يَحِيفَ اللَّهُ عَلَيْهِمْ وَرَسُولُهُ ۚ بَلْ أُولَٰئِكَ هُمُ الظَّالِمُونَ
And when they are called to Allah (i.e. His Words, the Qur’an) and His Messenger to judge between them, lo! a party of them refuse (to come) and turn away. But if the right is with them, they come to him willingly with submission. Is there a disease in their hearts? Or do they doubt or fear lest Allah and His Messenger should wrong them in judgement. Nay, it is they themselves who are the Zalimun (polytheists, hypocrites and wrong-doers, etc.).[24:48-50] This is the disease of Shubhah [i.e. an affair of falsehood that is made to resemble truth] and Shak [i.e. doubt].
As for the disease of Shahwa [evil desires], Allaah [The Most High] said: [يَا نِسَاءَ النَّبِيِّ لَسْتُنَّ كَأَحَدٍ مِّنَ النِّسَاءِ ۚ إِنِ اتَّقَيْتُنَّ فَلَا تَخْضَعْنَ بِالْقَوْلِ فَيَطْمَعَ الَّذِي فِي قَلْبِهِ مَرَضٌ – O wives of the Prophet! You are not like any other women. If you keep your duty (to Allah), then be not soft in speech, lest he in whose heart is a disease [i.e. evil desire for adultery, etc.] should be moved with desire, but speak in an honourable manner.” [Ahzaab: Ayah:32] This is the disease of the evil desire for adultery, and Allaah knows best.
As for the diseases of the body, Allaah [The Most High] said: [لَّيۡسَ عَلَى ٱلۡأَعۡمَىٰ حَرَجٌ۬ وَلَا عَلَى ٱلۡأَعۡرَجِ حَرَجٌ۬ وَلَا عَلَى ٱلۡمَرِيضِ حَرَجٌ۬ – There is no restriction on the blind, nor any restriction on the lame, nor any restriction on the sick….. [24:61]
Allaah mentioned the diseases of the body when He [The Most High] spoke about Hajj, Fasting and Ablution due to a marvellous underlying reason – a reason that will reveal to you the Greatness of the Qur’aan and suffices the one who understands it. The principles of physical medicine are three: preservation of health, protecting [the body] from what might cause harm and removal of harmful substances [from the body]; and Allaah [Glorified be He and free is He from all imperfections] mentioned these three principles in those three places [i.e. when He (The Most High) spoke about Hajj, Fasting and Ablution)] [Ref 1]
Imaam As-Sadi [rahimahullaah] said: Allaah (The Most High) said: [فِي قُلُوبِهِمْ مَرَضٌ -In their hearts is a disease]. [Surah Ayah: 10 Soorah Al-Baqarah]- What is intended by disease here is: The disease of doubt, the disease of Shubuhaat [i.e. affairs that resemble truth but are falsehood in reality] and the disease of hypocrisy. That is because the heart is exposed to two (types) of diseases that takes it away from well-being and uprightness- the disease of shubuhaat and the disease of lowly destructive desires. Disbelief, hypocrisy, doubts and bidah are all from the disease of Shubuhaat. Fornication, love of lewd acts, disobedience and committing them are from the disease of lowly desires. [Ref 2]
Allaah [The Most High] said: [وَنُنَزِّلُ مِنَ ٱلۡقُرۡءَانِ مَا هُوَ شِفَآءٌ۬ وَرَحۡمَةٌ۬ لِّلۡمُؤۡمِنِينَۙ – And We send down from the Qur’an that which is a healing and a mercy to those who believe (in Islamic Monotheism and act on it)]. [Soorah Al-Israa: Ayah 82]
Imaam Ibnul Jawzi (rahimahullaah) said: There are three statements (of the scholars) regarding the Qur’aan being a healing: [a] It is a healing for misguidance due to what it contains of guidance; [b] It is healing for illnesses due to what it contains of blessings; [c] It is healing due to its explanation and clarification of the obligatory duties and rulings of the religion. [Ref 3]
Imaam Ibnul Qayyim (rahimahullaah) said: The Qur’aan is a healing for the hearts for the diseases of ignorance, doubt and scepticism. Allaah (The Most High) has never revealed a cure that is neither more comprehensive and beneficial; nor greater and quicker in removing diseases than the Qur’aan.’’ [Ref 4]
Imaam Sadi (rahimahullaah) said: The healing that the Qur’aan contains covers all [diseases] of the hearts, such the disease of Shubhah [(i.e. an affair that is made to resemble truth but is falsehood in reality], ignorance, corrupt views, perversion and evil aims; for indeed the Qur’aan is gathered upon ‘Al-Ilm Al-Yaqeenee [i.e. Knowledge based on Absolute Certainty’ by way of which every Shubhah and affair of ignorance is removed, and it contains an admonition and a reminder by way of which every desire that is in opposition to the command of Allaah is removed]. And it is a healing for the bodies against what is harmful to them and its illnesses. As for it being a Mercy, it is due to the Asbaab [i.e. sound means] and Wasaa-il [i.e. paths, ways] it guides to, which if the slave [i.e. person] acts upon them, he (or she) will be successful (in receiving Allaah’s) Mercy and an everlasting happiness-reward in this worldly life and everlasting reward in the Hereafter. [Ref 5]
Imaam Shanqeeti (rahimahullaah) said: It (i.e. the Qur’aan) combines healing for the diseases of the heart, such as doubt, hypocrisy and other than that. It is a healing for the bodies when utilised for ruqya, such as what took place in the story of the man who performed ruqya with Soorah Faatihah on a man who was stung and it is an authentic and famous story…. [Ref 6]
Ref 1: Source: At-Tib An-Nabawiy of Imaam Ibnul Qayyim Al-Jawziyyah (rahimahullaah) with comments by Al-Allaamah Muhammad Haamid Al-Faqee (rahimahullaah): page: 3. Abridged and slightly paraphrased]. Your feedback is welcome to improve the content of this article BaarakAllaahu Feekum
[Ref 2: Source: Tafseer Sadi Soorah Al-Baqarah]
[Ref 3: Source: Zaadul Maseer Fee Ilm At-Tafseer of Ibnul Jawzi (rahimahullaah)—Tafseer Soorah al-Israa]
[Ref 4: Al-Jawaab Al-Kaafee page 4]
[Ref 5: Tafseer As-Sadi]
[Ref 6: Adwaa Al-Bayaan–Tafseer Soorah Al-Israa: Ayah 82]