Abu Dawud
Purification (Kitab Al-Taharah)
Book Number: 001 / Hadith Number: 97
Narated By Abdullah ibn Mughaffal : Abdullah heard his son praying to Allah: O Allah, I ask Thee a white palace on the right of Paradise when I enter it. He said: O my son, ask Allah for Paradise and seek refuge in Him from Hell-Fire, for I heard the Messenger of Allah (pbuh) say: In this community there will be some people who will exceed the limits in purification as well as in supplication.