Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) said:
Whoever plays these instruments as a form of worship is undoubtedly misguided and ignorant. But if he does it as a form of entertainment, then the view of the four imams is that all musical instruments are haraam. It is proven in Saheeh al-Bukhaari and elsewhere that the Prophet (peace and blessings of Allaah be upon him) said that there would be among his ummah those who regarded zina, silk, alcohol and musical instruments as halaal, and he said that they would be transformed into monkeys and pigs.
Majmoo’ al-Fataawa (11/576, 577).