Is it true that whoever deems musical instruments permissible is considered an apostate (kafir), even if they do not listen to them?

Permitting what is forbidden is an act of disbelief (kufr) when it pertains to clear, universally agreed-upon prohibitions whose sacredness is known to all. Therefore, whoever believes something to be permissible that is unanimously forbidden, and whose ruling is evident among Muslims, and concerning which all ambiguity has been removed—such as the texts regarding pork and fornication—has committed disbelief.

Ibn Taymiyyah said: "Whenever a person permits what is forbidden by consensus, or forbids what is permissible by consensus, or alters the universally agreed-upon law, he becomes a disbeliever, an apostate, by agreement of the jurists." Also, whoever denies the obligation of clear, oft-repeated duties, or denies the prohibition of clear, oft-repeated forbidden things, or denies the permissibility of clear, oft-repeated permissible things, is a disbeliever.

The prohibition of musical instruments (ma'azif) is not known to be a necessity of religion, nor is it a matter of definitive consensus, nor is its ruling commonly shared among people. Given the many interpretations and ambiguities surrounding it, it is not correct to rule that whoever deems it permissible has committed disbelief.