Musnad Ahmad 28:172

Hassan narrated to us, Ibn Lahi'ah narrated to us, Al-Harith ibn Yazid narrated to us from Ali ibn Rabah, who said: I heard Abdullah ibn Amr saying: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Indeed, the guided Muslim attains the rank of the one who fasts and prays throughout the night by the verses of Allah, through his good character and the nobility of his nature."