Hadith - Qudsi 10

Fasting is Mine and it I who give reward for it. [A man] gives up his sexual passion, his food and his drink for my sake. Fasting is like a shield, and he who fasts has two joys: a joy whin he breaks his fast and a joy when he meets his Lord. The change in the breath of the mouth of him who fasts is better in Allah’s estimation than the smell of musk.

Hadith - Al-Tirmidhi, Narrated ‘Aisha, r.a.

Allah’s Messenger (peace be upon him) used to fast on Mondays and Thursdays.

Tirmidhi and Nasa’i transmitted it.

The Noble Qur’an Al-Baqarah 2:183-185, 187

O you who believe! Observing As-Saum (the fasting)[] is prescribed for you as it was prescribed for those before you, that you may become Al-Muttaqûn (the pious - see V.2:2).

[Observing Saum (fasts)] for a fixed number of days, but if any of you is ill or on a journey, the same number (should be made up) from other days. And as for those who can fast with difficulty, (e.g. an old man, etc.), they have (a choice either to fast or) to feed a Miskîn (poor person) (for every day). But whoever does good of his own accord, it is better for him. And that you fast, it is better for you if only you know.[]

The month of Ramadân in which was revealed the Qur’ân, a guidance for mankind and clear proofs for the guidance and the criterion (between right and wrong). So whoever of you sights (the crescent on the first night of) the month (of Ramadân i.e. is present at his home), he must observe Saum (fasts) that month, and whoever is ill or on a journey, the same number [of days which one did not observe Saum (fasts) must be made up] from other days. Allâh intends for you ease, and He does not want to make things difficult for you. (He wants that you) must complete the same number (of days), and that you must magnify Allâh [i.e. to say Takbîr (Allâhu-Akbar; Allâh is the Most Great) on seeing the crescent of the months of Ramadân and Shawwâl] for having guided you so that you may be grateful to Him.[]

It is made lawful for you to have sexual relations with your wives on the night of As-Saum (the fasts). They are Lîbas [i.e. body cover, or screen, or Sakan, (i.e. you enjoy the pleasure of living with her - as in Verse 7:189) Tafsir At-Tabarî], for you and you are the same for them. Allâh knows that you used to deceive yourselves, so He turned to you (accepted your repentance) and forgave you. So now have sexual relations with them and seek that which Allâh has ordained for you (offspring), and eat and drink until the white thread (light) of dawn appears to you distinct from the black thread (darkness of night), then complete your Saum (fast) till the nightfall. And do not have sexual relations with them (your wives) while you are in I’tikâf (i.e. confining oneself in a mosque for prayers and invocations leaving the worldly activities) in the mosques. These are the limits (set) by Allâh, so approach them not. Thus does Allâh make clear His Ayât (proofs, evidences, lessons, signs, revelations, verses, laws, legal and illegal things, Allâh’s set limits, orders, etc.) to mankind that they may become Al-Muttaqûn (the pious - see V.2:2).