It is narrated from Sayyiduna Abu Malik al-Ash'ari (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "In Paradise there are chambers whose outside can be seen from their inside and their inside from their outside. Allah, the Mighty and Majestic, has prepared them for the one who feeds others, fasts continually, and prays at night while people are asleep."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3454