Bulugh al-Maram 2 The Book of Prayer كتاب الصلاة 256

وَعَنْ أُمِّ حَبِيبَةَ أُمِّ اَلْمُؤْمِنِينَ -رَضِيَ اَللَّهُ عَنْهَا- قَالَتْ : سَمِعْتَ اَلنَّبِيَّ – صلى الله عليه وسلم -يَقُولُ : { مَنْ صَلَّى اِثْنَتَا عَشْرَةَ رَكْعَةً فِي يَوْمٍ وَلَيْلَةٍ بُنِيَ لَهُ بِهِنَّ بَيْتٌ فِي اَلْجَنَّةِ } رَوَاهُ مُسْلِمٌ . وَفِي رِوَايَةٍ ” تَطَوُّعًا” . 1 1 – صحيح . رواه مسلم (728 ) .

Narrated Umm Habibah (RA) the Mother of the Believers: She heard Allah’s Messenger (صلى الله عليه وسلم) say, “Whoever prays twelve (voluntary) Rak’at in a day and a night, a house will be built for him in Paradise due to them (the Rak’at).” [Reported by Muslim]. In another narration, it is mentioned: “Voluntarily”.