The primary source for the obligation and sanctity of Ramadan is the Quran itself. Allah declares, “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”. This verse immediately establishes the profound honor bestowed upon Ramadan: it is the month chosen for the revelation of the Holy Quran, a universal guide for humanity, distinguishing truth from falsehood. Tafsir scholars like Ibn Kathir and the authors of Ma'arif-ul-Quran elaborate on this, explaining that not only the Quran but also other divine scriptures, such as the Suhuf of Ibrahim, the Torah, and the Injil, were revealed in Ramadan. While these earlier books were revealed on specific dates, the Quran's unique revelation involved its descent from the Preserved Tablet to the earthly heaven in one night of Ramadan, specifically Laylat al-Qadr, before being gradually revealed to Prophet Muhammad over 23 years. This momentous event underscores Ramadan's significance as a period intrinsically linked to divine guidance.

The verse then directly issues the commandment to fast: “So whoever sights the new moon of the month, let him fast it”. This makes fasting obligatory for every Muslim who is present and capable during the month. Ma'arif-ul-Quran clarifies that "witnessing the month" implies being a Muslim, sane, pubert, resident, and free from ritual impurities. This mandate supersedes any earlier options, such as paying a ransom (fidyah) for not fasting, making sawm the sole alternative. The obligation begins with the sighting of the new moon of Ramadan, or by completing thirty days of Sha'ban if the moon is not sighted due to weather, as affirmed by various hadith, including one where [the Prophet (ﷺ) said, "When you see the crescent (of the month of Ramadan), start fasting, and when you see the crescent (of the month of Shawwal), stop fasting; and if the sky is overcast (and you can't see it) then regard the month of Ramadan as of 30 days"]Bukhari 30:10. This lunar observation or completion of Sha'ban sets the precise duration of the fasting period.

The life and teachings of Prophet Muhammad (peace be upon him) serve as the ultimate commentary and practical application of the Quranic mandate. His actions and words during Ramadan illuminate the spiritual depth intended by Allah. Abu Huraira narrates that [Allah's Messenger (ﷺ) was the most generous of all the people, and he used to reach the peak in generosity in the month of Ramadan when Gabriel met him]Bukhari 1:6. This remarkable generosity, described as "more generous than the strong uncontrollable wind," was particularly pronounced as Gabriel used to meet him every night of Ramadan to teach and revise the Qur'an Bukhari 1:6Bukhari 30:12Bukhari 59:31Bukhari 61:63. This highlights the Prophet's dedication to the Quran and charity during this sacred month, setting a powerful example for Muslims.

Beyond personal piety, the Prophet also emphasized the rewards for specific acts of worship in Ramadan. He stated, [Whoever establishes prayers during the nights of Ramadan faithfully out of sincere faith and hoping to attain Allah's rewards (not for showing off), all his past sins will be forgiven]Bukhari 2:30. Similarly, [whoever fasts in the month of Ramadan out of sincere faith, and hoping for a reward from Allah, then all his previous sins will be forgiven]Bukhari 30:11. These hadith underscore the immense spiritual benefits of sincere devotion during Ramadan, linking fasting and night prayers (Tarawih) directly to the forgiveness of sins, a central theme of purification. The Messenger of Allah (ﷺ) also said, [When the month of Ramadan starts, the gates of the heaven are opened and the gates of Hell are closed and the devils are chained]Bukhari 30:9, indicating a uniquely auspicious spiritual environment.

While fasting in Ramadan is an obligation, Islam's inherent principle of ease (yusr) provides specific exemptions. The Quran states, 2:185. Both Tafsir al-Jalalayn and Ibn Kathir confirm that this verse reiterates and confirms the concession for the sick and travelers, ensuring that the general obligation of fasting did not abrogate this mercy. They emphasize that Allah desires ease for His servants, allowing them to break their fast and make up the missed days later.

The Sunnah provides practical guidance on these exemptions. The Prophet (ﷺ) himself sometimes fasted and sometimes broke his fast during journeys. Ibn `Abbas reported that [Allah's Messenger (ﷺ) set out from Medina to Mecca and he fasted till he reached 'Usfan, where he asked for water and raised his hand to let the people see him, and then broke the fast, and did not fast after that till he reached Mecca, and that happened in Ramadan]Bukhari 30:55. Ibn Kathir cites a hadith where the Prophet stated about fasting while traveling: [Those who did not fast have done good, and there is no harm for those who fasted](Ibn Kathir, quoting Prophet (ﷺ)). However, if fasting becomes difficult during travel, breaking it is better, as the Prophet (ﷺ) explicitly said: [It is not a part of Birr (piety) to fast while traveling](Bukhari, Muslim, quoting Prophet (ﷺ)). The emphasis is always on ease, as reflected in the Prophet's general guidance: [Treat the people with ease and don't be hard on them; give them glad tidings and don't fill them with aversion](Ibn Kathir, quoting Prophet (ﷺ) in Bukhari/Muslim). This flexibility ensures that the spiritual benefit of fasting is not overshadowed by undue hardship.

Islamic jurisprudence, informed by the Quran and Sunnah, outlines specific rulings concerning the observance of Ramadan and its violations. The obligation to fast applies to every Muslim who "finds" the month in a state of ability. Ma'arif-ul-Quran details that if a disbeliever embraces Islam, a minor becomes pubert, an insane person regains sanity, a menstruating woman becomes pure, a sick person recovers, or a traveler returns home during Ramadan, they must begin fasting from that point, and in some cases, make up for previously missed days.

A significant legal ruling concerns the expiation for breaking a fast intentionally by engaging in sexual intercourse during Ramadan. Numerous hadith describe a scenario where a man confessed to the Prophet (ﷺ) that he had sexual relations with his wife while fasting in Ramadan. The Prophet (ﷺ) prescribed a graded expiation: first, to [manumit a slave]Bukhari 30:44Muslim 13:103; if unable, then to [fast for two successive months]Bukhari 30:44Muslim 13:103; and if still unable, then to [feed sixty poor persons]Bukhari 30:44Muslim 13:103. In one instance, when the man claimed he was the poorest in Medina and couldn't feed others, the Prophet (ﷺ) smiled and told him to [feed your family with it]Bukhari 30:44Bukhari 51:34Bukhari 69:18Bukhari 78:115Bukhari 78:190Bukhari 84:2Bukhari 84:3Bukhari 84:4. This incident highlights the compassionate nature of Islamic law, balancing divine rights with human limitations and needs, while establishing a serious consequence for violating the sanctity of the fast.

Another important legal aspect is Sadaqat al-Fitr, a charitable payment due at the end of Ramadan. Ibn `Umar narrated that [The Prophet (ﷺ) made incumbent on every male or female, free man or slave, the payment of one Sa' of dates or barley as Sadaqat-ul-Fitr (or said Sadaqa-Ramadan)]Bukhari 24:111Muslim 12:16Muslim 12:18Muslim 12:20. This purification offering is due on behalf of every Muslim, young or old, before the Eid prayer, ensuring the poor can also celebrate the festival.

The last ten nights of Ramadan hold immense spiritual value, primarily because they contain Laylat al-Qadr (the Night of Power or Ordainment). The Quran mentions this night as when [the angels and the Spirit descend therein by permission of their Lord for every matter](Introduction). Tafsir al-Jalalayn and Ibn Kathir both link the Quran's revelation to this blessed night. The Prophet (ﷺ) actively encouraged Muslims to seek this night, stating, [Look for the Night of Qadr in the last ten nights of the month of Ramadan]Bukhari 32:7. Specific guidance was given to search for it in the odd nights: [Look for it on the 29th, 27th and 25th (of Ramadan)]Bukhari 32:10. Although its exact date was once known to the Prophet (ﷺ), it was then caused to be forgotten due to a quarrel, possibly for the good, encouraging more widespread worship Bukhari 32:10Muslim 13:280.

To maximize the chances of encountering Laylat al-Qadr and deepen spiritual connection, the Prophet (ﷺ) regularly practiced I'tikaf, a spiritual retreat in the mosque during the last ten days of Ramadan. `Aisha (Allah be pleased with her) reported that [Allah's Messenger (ﷺ) used to practice I`tikaf in the last ten nights of Ramadan till he died and then his wives used to practice I`tikaf after him]Bukhari 33:2Muslim 14:5. This practice involves secluding oneself in the mosque for concentrated worship, prayer, and recitation of the Quran, detaching from worldly affairs. The Prophet's wives also pitched tents to perform I'tikaf, indicating its significance Bukhari 33:8Muslim 14:6. This intensive period of devotion reflects the ultimate goal of Ramadan: to achieve heightened awareness of Allah and secure His forgiveness and mercy.

In conclusion, Ramadan is a multifaceted pillar of Islam, deeply rooted in divine revelation and meticulously expounded through prophetic tradition. It is a month not only for physical abstinence but for comprehensive spiritual growth, moral rectification, and communal solidarity. From the Quran's initial declaration of its sanctity as the month of divine revelation to the Prophet's practical guidance on fasting, charity, prayer, and seeking Laylat al-Qadr, Ramadan provides a holistic framework for spiritual transformation. The legal traditions further operationalize these injunctions, ensuring ease and justice for all believers. Ultimately, Ramadan is a profound annual opportunity for Muslims to glorify Allah for His guidance and express gratitude, fostering purification of the soul and a renewed commitment to the Straight Path.