´It was narrated that Umm Habibah said:` "Whoever prays twelve rak'ahs during the night and day apart from the prescribed prayers, Allah (SWT), the Mighty and Sublime, will build for him a house in Paradise."
Hadith ReferenceSunan an-Nasa'i / The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day / Hadith: 1807