Hazrat Abu Bakhtari narrates that in the time of the Holy Prophet (peace and blessings be upon him), there was a woman who used to fast but did not guard her tongue. When the Messenger of Allah (peace and blessings be upon him) came to know of this, he said that her fast was not valid. When she began to guard her tongue, he said that soon her fast would become valid. When she guarded it even more, he said that now her fast was valid.

Hazrat Mujahid says that the fast of the one who avoids these two traits will remain intact: one is backbiting and the other is lying.

Ibrahim says that the predecessors used to say that lying breaks the fast.

Hazrat Abu Alia says that a fasting person remains in worship as long as he does not backbite.

It is narrated from Hazrat Anas that the Messenger of Allah, peace and blessings be upon him, said: Whoever continues to eat the flesh of people, his fast is not valid.

Hazrat Mutarrif bin Abdullah bin Shikhir says that I once visited Hazrat Usman bin Abi Al-Aas. He had milk from a pregnant she-camel brought for me. I said that I am fasting. He said that I heard the Messenger of Allah, peace and blessings be upon him, say that fasting is a shield against Hell just as you take a shield against an enemy. The best way to fast is to keep three fasts every month.

Hazrat Abdullah said that fasting is a shield against Hell just as any one of you uses a shield as a weapon to the best of his ability against an enemy.

It is narrated from Hazrat Abu Huraira and Hazrat Abu Saeed that the Messenger of Allah, peace and blessings be upon him, said that Allah Almighty says: Fasting is for Me and I alone give its reward. There are two joys for the fasting person: one at the time of breaking the fast, when he is happy, and the other when he meets his Lord and he will be happy. By the One in Whose hand is my soul, the smell from the mouth of the fasting person is more beloved to Allah than the fragrance of musk.

It is narrated from Hazrat Abu Huraira that the Messenger of Allah, peace and blessings be upon him, said: Every deed of the son of Adam is multiplied. The reward of a good deed is increased from ten times to seven hundred times. Allah Almighty says: Except for fasting, for it is for Me and I alone will give its reward. The fasting person leaves his food and his desires for My sake. There are two joys for the fasting person: one is the joy he feels at the time of breaking his fast, and the other is the joy he will feel when he meets his Lord. The smell from the mouth of the fasting person is more beloved to Allah than musk. Fasting is a shield, fasting is a shield.

Hazrat Abu Umamah narrates that I asked, "O Messenger of Allah! Tell me about an action that will admit me to Paradise." You replied, "Observe fasting, for there is nothing like it." After that, the state of Hazrat Abu Umamah was such that smoke would be seen coming from his house only when there was a guest in his home.