"Singing and music is a nest for the bird called hypocrisy."

The sixth Holy Imam, Imam Ja'far as-Sadiq (a.s.) said, 

"Listening to music, songs and useless words cultivate hypocrisy in the heart, in the same way as algae grows in water." 
(Al Kafi)

The same book, Al Kafi mentions a tradition of Imam as-Sadiq (a.s.) that,

"Singing and music is a nest for the bird called hypocrisy."

The Holy Prophet (s.a.w.s.) says: 

"Calamities will befall my Ummat as sinking of the earth and rain of stones."

The people asked, "When would it happen?" 

"When the instruments of music become common, singing girls are in great number and the use of intoxicants is widespread. By Allah, many people of my Ummat will be such that they shall spend the night in merry-making and sensuality and in the daytime become like monkeys and pigs. It will be the consequence of considering the prohibited things permissible, they will be occupied with singing girls, frequently take intoxicants, devour interest and shall dress in clothes made of silk."