Excerpts from the ‘Jurisprudence of Worship’
By Shaykh Muhammad ibn Saalih ibn Uthaymeen رحمه الله تعالى

Question: Oh Noble Shaykh, What is the ruling of fasting the month of Ramadān?

Answer:
Fasting the month of Ramadān has been obligated by the Quran and Sunnah (prophetic traditions of Prophet Muhammad صلى الله عليه وسلم) and consensus of the Muslims (الإجماع ).

Allāh said: تبارك وتعالى
يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُواْ كُتِبَ عَلَيۡكُمُ ٱلصِّيَامُ كَمَا كُتِبَ عَلَى ٱلَّذِينَ مِن قَبۡلِكُمۡ لَعَلَّكُمۡ تَتَّقُونَ¹
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-Muttaqun (the pious – see V. 2:2). ²

Until Allāh speech:
شَهۡرُ رَمَضَانَ ٱلَّذِيٓ أُنزِلَ فِيهِ ٱلۡقُرۡءَانُ هُدٗى لِّلنَّاسِ وَبَيِّنَٰتٖ مِّنَ ٱلۡهُدَىٰ وَٱلۡفُرۡقَانِۚ فَمَن شَهِدَ مِنكُمُ ٱلشَّهۡرَ فَلۡيَصُمۡهُ³

The month of Ramadan in which was revealed the Quran, 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 Ramadan i.e. is present at his home), he must observe Saum (fasts) that month.⁴

The Prophet Muhammad ﷺ said: “Islām has been built on five [pillars]: testifying that there is no deity worthy of worship except Allāh and that Muhammad is the Messenger of Allāh, establishing the Salāh (prayer), paying the Zakāh (obligatory charity), making the Hajj (pilgrimage) to the House (Al-K’abah), and the fasting of Ramadān.”⁵

And he ﷺ also said:
“If you see it (the crescent moon of the month Ramadān- signaling the beginning of the month) then observe fast.”⁶

And the consensus of the Muslims upon fasting the month of Ramadān is that it is obligatory and that verily it is one of the pillars of Islām. So whomever negates the obligations of fasting the month of Ramadān has disbelieved except if he had an upbringing in a distant land and the people there do not know the rulings of Islām. So he is excused for that (his negation without knowledge). Then if he insists (upon his negation) after establishing the evidence upon him, he has disbelieved. And whomever leaves it off (the fasting of Ramadān) with the acknowledgement of it’s obligation then he is in danger. For verily some of the people of knowledge have ruled (upon such an individual) that he is a disbeliever. However, the correct opinion is that he is not a disbeliever/apostate instead he is an immoral sinner from the sinful in immense danger.

¹Al Quran- [Surah Al-Baqarah, Ayah 183]
²Noble Quran- Surah Al-Baqarah Ayat 183 [Muhsin Khan and Taqi-ud-Din al-Hilali]
³Al-Quran- [Surah Al-Baqarah, Ayah 185]
⁴Noble Quran- Surah Al- Baqarah, Ayah 185 [Muhsin Khan and Taqi-ud-Din al-Hilali]
⁵Related by Bukhari- Book of Belief, Chapter your Supplication and your Belief [Number 8] and related Muslim Book of Belief [number 16].
⁶Related by Bukhari- Book of Fasting, [number 1901] and related by Muslim- Book of Prayers of the Travelers [number 760].

Jurisprudence of Worship- Fatwa For Sâum (Fasting) (Pg.244-245)

Translated by: Abu Uwāis, Muhammad Abdullahi Elmi