Musannaf Ibn Abi Shayba 2:51

Abu Bakr narrated to us, he said: Yahya ibn Abi Bukayr narrated to us, he said: Ya’la (Ali) ibn al-Harith narrated to us, from Ubayd Allah ibn Muslim, he said: I heard the mu'adhdhin of Umar ibn Abd al-Aziz saying: "Prayer is better than sleep."