(35) Hadhrat Abu Burzah (radhiyallahu anhu) narrated: "We were with the Nabi (sallallahu alayhi wasallam) o­n a journey when he heard two men singing. The o­ne was responding to the other (by means of singing poetry). Nabi (sallallahu alayhi wasallam) then said: 'Look who these two are.' They (the Sahaabah) said: 'They are so and so (naming them).' Rasulullah (sallallahu alayhi wasallam) then cursed, saying: 'O Allah! Cast them upside down in Jahannum." (Majmauz Zawaaid)

The gravity of the prohibition of singing and music should be apparent from the vehemence of the curse of Rasulullah (sallallahu alayhi wasallam).