Sunan an-Nasa'i 1805
سنن النسائي#1805SahihIt was narrated that Umm Habibah said:"Whoever prays twelve rak'ahs during the night and day apart from the prescribed prayers, a house will be built for him in Paradise
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 20:208