Apostasy in Islam
Most Sunni Islam and the Twelvers Shi'a Islamic schools of thought agree that apostasy is a sin. There is a difference between harmful apostasy and harmless apostasy (also known as major and minor apostasy).  According to Wael Hallaq, none of the apostasy laws are based on the Qur'an, although the jurist al-Shafi'i interpreted the Qu'ranic verse 2:217 as proof that apostasy is outlawed. This provided the main evidence for apostasy being a capital crime in Islam. Sharia --Islamic law-- says the punishment for apostasy should be death, but the Qu'ran does not have any instructions for punishing apostasy.