What is the ruling on a Person of the Book who converts to a religion whose adherents are not recognized by the state (e.g., idol worship)?
Chapter on What is Prohibited to Marry and Combining Between Them and Other Matters
Al-Mughni
Book of Marriage
Primary text
If a Person of the Book converts to a religion whose adherents are not permitted to pay the Jizyah (poll tax), such as idolatry or other self-devised creeds, he is not to be affirmed in that new religion. This is because the original adherents of that creed are not accepted, so the convert is less likely to be accepted. If he converts to Magianism, he is also not affirmed, as this is a lesser religion than his previous one, akin to a Muslim apostatizing.
Supporting text
If a Person of the Book converts to another religion within the category of the People of the Book, such as a Jew becoming a Christian or a Christian becoming a Jew, there are two narrations. One holds that he is not affirmed because he moved to a false religion whose falsehood he previously acknowledged, similar to an apostate. The second narration, narrated by Ahmad, states he is affirmed, which is also the apparent view of Al-Khiraqi, the choice of Al-Khallal and his companion, and the view of Abu Hanifah. This second view holds that since he has not left the category of the People of the Book, he is treated like one who did not convert. Al-Shafi'i has two opinions, corresponding to these two narrations. Similarly, if a Magian converts to a religion whose adherents are not affirmed, he is not affirmed. The rulings regarding conversion apply equally to men and women based on the general statement of the Prophet, peace be upon him: 'Whoever changes his religion, kill him,' and the general underlying reasoning applies to both.