Musannaf Ibn Abi Shaybah

Hazrat Bajalah bin Abadah, may Allah have mercy on him, narrates that Hazrat Umar, may Allah be pleased with him, wrote a letter to Hazrat Abu Musa, may Allah have mercy on him: Present this matter to the Magians who are with you, that they should give up marrying their mothers, daughters, and sisters. And that they should eat in silence, and that they should be included among the People of the Book. And kill every male and female magician.