Prayer (Kitab Al-Salat): Detailed Injunctions about Witr
Dawud :: Book 8 : Hadith 1543
Narrated AbuHurayrah:
The Apostle of Allah (peace_be_upon_him) used to say: "O Allah, I seek refuge in Thee from four things: Knowledge which does not profit, a heart which is not submissive, a soul which has an insatiable appetite, and a supplication which is not heard."