Sayyiduna Abu Malik al-Ash'ari (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "Indeed, in Paradise there is a chamber whose inside can be seen from its outside and whose outside can be seen from its inside. Allah has prepared it for those who speak gently, feed others, fast continually, and pray when people are asleep."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8479