‏الصلاة : Hadeeth No:1677 Ibn 'Abbas said: I spent the night in the house of my mother's sister, Maimuna, and observed how the Messenger of Allaah (sallAllaahu alayhi wa sallam) prayed (at night). He got up and relieved himself. He then washed his face and hands and then went to sleep. He again got up and went near the water...

‏الصلاة : Hadeeth No:1580 Nu'man b. Salim reported with the same chain of transmitters: He who observed twelve voluntary rak'ahs, a house will be built for him in Paradise....