Musnad Abu Ya'la al-Mawsili 140:22

Ibrahim ibn al-Hajjaj al-Nayli narrated to us, Salih narrated to us, from Thabit, Ja'far ibn Zayd, Yazid al-Raqashi, and Maymun ibn Siyah, from Anas, who said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) saying: "Whoever prays the morning prayer, he is under the protection (dhimmah) of Allah. So beware, lest Allah should seek from you anything regarding His protection."