The Qur'anic teaching about fasting

Allah Almighty has made fasting obligatory on Muslims.

یٰۤاَیُّہَا الَّذِیۡنَ اٰمَنُوۡا کُتِبَ عَلَیۡکُمُ الصِّیَامُ کَمَا کُتِبَ عَلَی الَّذِیۡنَ مِنۡ قَبۡلِکُمۡ لَعَلَّکُمۡ تَتَّقُوۡنَ اَیَّامًا مَّعۡدُوۡدٰتٍ ؕ

Surah #02 | Ayat #183 & 184

  O you who have believed, decreed upon you is fasting as it was decreed upon those before you that you may become righteous - [Fasting for] a limited number of days.

While this verse indicates the necessity of fasting, it also shows that this phrase was not only specific to Islam but was also found in the earlier nations. According to some traditions, even in the most ignorant days, they used to fast as a form of worship. According to Sahih Bukhari, in the time of Jahiliyyah, the Quraysh used to fast on the tenth of Muharram. The Holy Prophet (peace and blessings of Allaah be upon him) had given the knowledge of fasting during the day at the very beginning of his career. When Allah allowed the fast of Ramadan to be observed on that Muharram and said: Whoever wants to fast should do so and whoever wants to miss so should leave. Since the 10th of Muharram is the day of martyrdom of Imam Hussain (AS), his children and his martyred companions, the Shia (Asna Ashriya) have now made the fast of this day undesirable and shitty. It is not surprising that the traditions of the virtues of Ashura have been fabricated by the Umayyads from the very beginning to diminish the importance of the rise of Imam Hussain (AS).  

In the above verse, a few days of counting means the time of Ramadan or the following verse shows that Ramadan is the month in which the Qur'an was revealed.

شَہۡرُ رَمَضَانَ الَّذِیۡۤ اُنۡزِلَ فِیۡہِ الۡقُرۡاٰنُ ہُدًی لِّلنَّاسِ وَ بَیِّنٰتٍ مِّنَ الۡہُدٰی وَ الۡفُرۡقَانِ ۚ

Surah: 2 | Ayat: 185

The month of Ramadhan [is that] in which was revealed the Qur'an, a guidance for the people and clear proofs of guidance and criterion.

Some people also say that a few days means three days of every month.  But those who say so are also convinced that it was abrogated by the knowledge of fasting in the short month of Ramadan. The above verse does not explain what is meant by fasting and how many times fasting is obligatory.  Nor is it clear what is permissible and what is not permissible for a fasting person. The details of these matters have been narrated by the Holy Prophet (SAWW). The Qur'an only knows about the sick and the traveler who are not allowed to fast and it is said that the traveler should make up the fast on his return from his journey. From the obvious verse, it is possible that it is obligatory to look after the patient and the traveler, because Allah has commanded us to break the fast only during the journey and in turn. This is the opinion of many Companions and others, including Hazrat Umar, Hazrat Ibn Abbas, Hazrat Ibn Umar and Hazrat Urwah bin Zubair. The belief of Shia’s in following their pure Imams is same. When Hazrat Umar was asked about the fast of the traveler, he said: If you give something to someone and he return, will you not get angry?  This is the religion of Allah. Abd al-Rahman ibn Awf said: Fasting while traveling is like not fasting in the head. It is narrated from Imam Ja'far Sadiq (AS) that if a person dies while traveling and he is fasting, then I will not offer his funeral prayers.

Allah says 

 وَ عَلَی الَّذِیۡنَ یُطِیۡقُوۡنَہٗ فِدۡیَۃٌ طَعَامُ مِسۡکِیۡنٍ ؕ فَمَنۡ تَطَوَّعَ خَیۡرًا فَہُوَ خَیۡرٌ لَّہٗ ؕ وَ اَنۡ تَصُوۡمُوۡا خَیۡرٌ لَّکُمۡ   اِنۡ کُنۡتُمۡ  تَعۡلَمُوۡنَ

Surah: 2 | Ayat: 184

  [Fasting for] a limited number of days. So whoever among you is ill or on a journey [during them] - then an equal number of days [are to be made up]. And upon those who are able [to fast, but with hardship] - a ransom [as substitute] of feeding a poor person [each day]. And whoever volunteers excess - it is better for him. But to fast is best for you, if you only knew. 

This verse is about those who are able to fast but do not fast at all. They should give food to a poor person at the end of every fast. That is, they can choose between the day and the stream. But in the sight of Allah, fasting is better than giving food. If this meaning of the verse is taken, then this knowledge will be considered to be abrogated from the second verse of Surah Baqarah:  Baqarah: verse 1) Regarding this verse, Ali ibn Abiramoon said: It is about the person who falls in love during the month and gets well after that.  If he makes up the missed fasts of the next Ramadan, he will have to make up the missed fasts, and he will have to give food to the poor because he did not fulfill this obligation without any excuse. According to the four religions of Ahl e Sunnah, if a person travels with all the conditions of a Shari'ah journey, he has the option of fasting and breaking the fast even if he wants to. They base their opinion on the hadiths which state that some of the companions of the Holy Prophet used to fast during their travels and some didn’t. In addition, he says: "Not fasting is for the convenience of the traveler and it can only be justified."