From "Tibb un Nabawiyy" of Shaykh Jalaluddin as Suyuti al Misri

Listening to melodious recitations (Qiraa'at) is the scent of souls, the calmer of hearts, the food of the spirit. It is among the most important kinds of psychological medicine. It is a cause of pleasure, even to some animals. And pleasure in moderation purifies the Innate Heat, strengthens the functioning of the Faculties, slows down senile decay by driving out its diseases, renders the complexion clearer, and refreshes the whole body. On the contrary, excess of pleasure makes the illnesses of the body to increase.

Abu Nu'aim Radhi Allahu 'anhu  in his Tibb-ul-Nabbi says of the Prophet Sall Allahu 'alaihi wa Aalihi wa sallim that he said that the advantages of listening to singing are increased by the understanding of it, that is, by its audibility. Allahu ta 'ala  Himself said: Give good news to my servants, those who listen to the Word and then follow the best of it. Quran 39.17

Abu Hurairah Radhi Allahu 'anhu said: Exalted are those who Almighty God has permitted among His permissions to His children to chant the Quran or to raise their voices in sweet songs or even to listen to them and to chant or recite in sweet cadences.

The Prophet Sall Allahu 'alaihi wa Aalihi wa sallim said: They enriched the Qur'an with their voices. And, . again, there occurs this saying of God: He increases in Creation what He pleases. Quran 35:1. This means through a beautiful voice.

Dhul-Nun was once asked: What is meant by singing? And he replied: It is the transporter of Truth and the Driver of hearts towards Truth. When asked about a beautiful voice he replied: It is words and accents to which Almighty God has added a perfume.

It is related of 'Umr bin al-Khattab Radhi Allahu 'anhu that he was chanting one day in his house. Some one remarked on it. To which he replied: Even if I am alone, I chant as is the custom of men. And he added: Song is the Provision of Travellers.

'Abd-Ullah bin Ja'far Radhi Allahu 'anhu was passionately fond of chanting. One day it was asked of al-Zuhri if he did not despise songs. To which he replied: Yes, when they are not pleasing, such for instance as are too dull or too frivolous.

The Prophet Dawud 'alaihi salaam was very sweet voiced when he used to recite. Whenever he recited the Psalms there used to collect around him jinns and men, birds and wild animals. Said the Prophet Sall Allahu 'alaihi wa Aalihi wa sallim to Abu Musa Radhi Allahu 'anhu: Verily I call this song one of the songs of the posterity of David.

Iindeed you will see that people of every laborious craft, such as dyers and porters, make up for themselves tunes and by this means dissipate their weariness. You will also see crying children quietened by a lullaby. Camels can be made to traverse long distances by songs. The story is told that a certain Arab possessed a very sweet voiced slave. He used to sing whenever a camel was very heavily loaded. Once such a camel accomplished a journey of three days in a single day. On arrival she lay down and died. If a camel was so affected by a sweet voice, even though it did not understand the meaning of the words, what then will people of taste and culture not think when they hear an exquisite voice and understand the beautiful words as well. You have seen the nightingales and the birds called shuhruir, how they seek for themselves places where they can listen to their singing.

On the legality of listening to songs, some doctors of the Law permit this pleasure, others do not. According to Ibn Qataba Radhi Allahu 'anhu songs and harmonious chants clarify the brain, sweeten the character, animate the soul, clear the blood, improve and help persons with thick diseases, and develop all the natural qualities of a man. Listening to singing is recommended in the treatment of some diseases, especially those due to spleen.

* The Melodious recitations Shaykh Jalaaluddin as Suyuti is referring to are the recitation of Holy Qur'an, songs in praise of Allahu ta 'ala and sending blessing on the Beloved Prophet Muhammmad Sall Allahu 'alaihi wa Aalihi wa sallim such as Qasidah Burda, Qasidah Muhammadiyya, Salawat ul Taj ( Darood Taj) etc.. This also includes poetry recounting events in Islamic history as well as poems composed to facilitate memorizing Islamic lessons such as Qasidah Aqidatul Awwam, Nurani Qaidah etc..  The melodious recitation of  certain verses of the Holy Qur'an and salawaat (Darood Sharif) have been successfully used for the treatment of physical and non-physical (spiritual) diseases.