Prophet of Rahmah, the Intercessor of Ummah, the Owner of Jannah (May Peace and blessings of Allah be upon him) said: ‘There is a portal in Heaven called Rayyan. On the Day of Judgement, this portal will be opened for those who fast (in the world); no one else will be allowed to enter through this portal. It will be announced, ‘Where are the people who used to fast?’ They will stand up and no one else will be allowed to enter through this portal. It will be closed after they enter the Heaven.
(Sahih Bukhari, pp. 148, Hadis 189)