This is a true religion.

This is a true religion.” They were pleased with his explanation and mutually decided that marriage with the nearest kin was permissible. Allah removed all knowledge from their hearts and lifted His Book from them. Now they are infidels and will go directly to Hell. Many reliable traditions mention that the Majus had a Prophet who was called Jaamaasp. He also brought a Book for them from Allah. That book was inscribed on the skin of twelve thousand cows.

They killed their Prophet and burnt down that Book. According to a reliable tradition, a miscreant asked some questions to Imam as-Sadiq and then became a Muslim. One of his questions was did the Majus also have any…