Muwatta Imam Malik (Riwayat Ibn al-Qasim)

And with this (chain of narration, it is narrated from Sayyiduna Abu Hurairah, may Allah be pleased with him) that the Prophet, peace and blessings be upon him, said: "Whoever spends two things (a pair) in the way of Allah, it will be said to him in Paradise: O servant of Allah! This (door) is better. The one who used to pray will be called from the door of prayer, the one who used to strive (in jihad) will be called from the door of jihad, the one who used to give charity will be called from the door of charity, and the one who used to fast will be called from the door of al-Rayyan (the door for those who fast)." Abu Bakr al-Siddiq, may Allah be pleased with him, said: "The one who is called from these doors will have no further need, but will there be anyone who will be called from all these doors?" The Prophet, peace and blessings be upon him, said: "Yes! And I hope that you will be among those (who will be called from all these doors)."

And with this chain (it is narrated from Sayyiduna Abu Hurairah, may Allah be pleased with him) that the Messenger of Allah, peace and blessings be upon him, said: "By Him in Whose hand is my soul! The smell from the mouth of a fasting person is more fragrant to Allah than the scent of musk. (Allah says:) He leaves his desires, food, and drink for My sake, so fasting is for Me and I alone will reward it. Every good deed is rewarded from ten times up to seven hundred times, except for fasting; it is exclusively for Me and I alone will reward it."