Musnad Ahmad 1012:8

Al-Walid ibn Muslim narrated to us, Al-Awza'i narrated to us, Umayr ibn Hani al-Ansi narrated to me, Junadah ibn Abi Umayyah narrated to me, he said: Ubadah ibn al-Samit narrated to me, from the Messenger of Allah, may Allah bless him and grant him peace, who said: "Whoever wakes up during the night and says: 'There is no god but Allah alone, He has no partner, to Him belongs the dominion, and to Him belongs the praise, and He is capable of all things. Glory be to Allah, and praise be to Allah, and Allah is the Greatest, and there is no power and no strength except by Allah,' then he says: 'O Lord, forgive me,' or he said: 'then he supplicated,' he will be answered. If he resolves [to pray], performs ablution, and then prays, his prayer will be accepted."