Musannaf Ibn Abi Shayba 13:2776

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Qays ibn al-Rabi’ narrated to us, from Khalid al-Hadhdha’, he said: Umar ibn Abd al-Aziz wrote regarding the Jew and the Christian: [They have the right of] pre-emption (shuf’ah).