Sunan Ibn Majah, Volume 2, Book 5, Hadith 1373 (DarusSalam) ⓘ
It was narrated that ‘Aishah said: “The Messenger of Allah said: ‘Whoever prays twenty Rak’ah between Maghrib and ‘Isha’, Allah will build for him a house in Paradise.’”
حَدَّثَنَا أَحْمَدُ بْنُ مَنِيعٍ، حَدَّثَنَا يَعْقُوبُ بْنُ الْوَلِيدِ الْمَدِينِيُّ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " مَنْ صَلَّى بَيْنَ الْمَغْرِبِ وَالْعِشَاءِ عِشْرِينَ رَكْعَةً بَنَى اللَّهُ لَهُ بَيْتًا فِي الْجَنَّةِ " .
also referenced under: Hadith 1373 (Reference) & Book 5, Hadith 1435 (In-Book)