وَنُنَزِّلُ مِنَ الْقُرْآنِ مَا هُوَ شِفَاءٌ وَرَحْمَةٌ لِلْمُؤْمِنِينَ
Wa-nunazzilu minal-qur’āni mā huwa shifā’un waraHmatun lil-mu’minin
We send down from the Quran what is a cure and a mercy to the faithful.
(Sūratul Isrā’ No. 17, Āyat 82)
Almighty Allah has revealed the Holy Quran as a healing and a mercy for believers. These two qualities of the Quran show special love of Allah for the faithful. The human being will fall sick during his stay on earth, both physically and spiritually, and will need a cure. After healing, special grace and mercy will be required to remain healthy and not fall sick again. So Allah sends down the rains of wisdom in the form of the Quran. His words will heal and strengthen those who are receptive and willing to be naturally human.
Describing the Quran as a cure and healing shows that believers are in need of a medicine that helps them revert to their original pure state. There was health (true original nature of the human being), then sickness (polluted and diseased soul) and then health again (cured by the wisdom of the Quran).
The Quran cures the diseases of the heart. It calms down the inner unrest and disturbances that threaten the stability of the spiritual heart. It is a medicine for sicknesses such as jealousy, selfishness, greed, apathy, etc. All āyat (i.e. Divine signs) of the Quran, especially those about the greatness of Allah and the beauty of creation, or verses that praise noble believers and describe their qualities, or āyāt that narrate the great dedication of the past prophets and their followers, affect the reader and enter the heart. Then they cleanse the insides and help get rid of the pollutants that have begun to seal the heart.
Amīrul Mu’minīn Imam Ali (a) talks about the Quran as a cure: Seek cure from it [the Quran] for your ailments, and seek its assistance in your distress. It contains a cure for the worst of the diseases, including disbelief, hypocrisy, rebellion, and misguidance (Nahjul Balāgha, Sermon 175).
Allow the Quran to heal you. Recite it when negative thoughts seem to overwhelm you, when you feel alone and need support. If you make the Quran your constant companion you will find yourself surprisingly healthy in all aspects. The sicknesses that weaken you will be cured and your increased spiritual health will allow you to tread firmly on the right path. There cannot be a better time and atmosphere than reciting the Holy Quran in the month of Ramadan. For it was revealed in it (Q 2:185) and the month is the spring of the Quran (Prophetic Hadith).
Source: Amīrul Mu’minīn, Nahjul Balāgha; Āyatullāh Nāsir Makārim Shirāzī (ed.), Tafsīr-e Namūne; ‘Allāmah S M H Tabātabā’ī