Umm Habibah (May Allah be pleased with her) the Mother of the Believers reported:
I heard the Messenger of Allah (ﷺ) saying, "A house will be built in Jannah for every Muslim who offers twelve Rak'ah of optional Salat other than the obligatory Salat in a day and a night (to seek the Pleasure of Allah)."[Muslim]. (FR)
App reference (FR): Book 9, Hadith 107 (FR)
Arabic/English book reference (FR): Book 9, Hadith 1097 (FR)