Tại sao người Muslim nhịn chay trong Ramadan?

يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ كُتِبَ عَلَيْكُمُ ٱلصِّيَامُ كَمَا كُتِبَ عَلَى ٱلَّذِينَ مِن قَبْلِكُمْ لَعَلَّكُمْ تَتَّقُونَ ﴿١٨٣﴾

O ye who believe! Fasting is prescribed for you, even as it was prescribed for those before you, that ye may ward off (evil);

شَهْرُ رَمَضَانَ ٱلَّذِىٓ أُنزِلَ فِيهِ ٱلْقُرْءَانُ هُدًۭى لِّلنَّاسِ وَبَيِّنَٰتٍۢ مِّنَ ٱلْهُدَىٰ وَٱلْفُرْقَانِ ۚ فَمَن شَهِدَ مِنكُمُ ٱلشَّهْرَ فَلْيَصُمْهُ ۖ وَمَن كَانَ مَرِيضًا أَوْ عَلَىٰ سَفَرٍۢ فَعِدَّةٌۭ مِّنْ أَيَّامٍ أُخَرَ ۗ يُرِيدُ ٱللَّهُ بِكُمُ ٱلْيُسْرَ وَلَا يُرِيدُ بِكُمُ ٱلْعُسْرَ وَلِتُكْمِلُوا۟ ٱلْعِدَّةَ وَلِتُكَبِّرُوا۟ ٱللَّهَ عَلَىٰ مَا هَدَىٰكُمْ وَلَعَلَّكُمْ تَشْكُرُونَ ﴿١٨٥﴾

The month of Ramadan in which was revealed the Qur'an, a guidance for mankind, and clear proofs of the guidance, and the Criterion (of right and wrong). And whosoever of you is present, let him fast the month, and whosoever of you is sick or on a journey, (let him fast the same) number of other days. Allah desireth for you ease; He desireth not hardship for you; and (He desireth) that ye should complete the period, and that ye should magnify Allah for having guided you, and that peradventure ye may be thankful.

أَيَّامًۭا مَّعْدُودَٰتٍۢ ۚ فَمَن كَانَ مِنكُم مَّرِيضًا أَوْ عَلَىٰ سَفَرٍۢ فَعِدَّةٌۭ مِّنْ أَيَّامٍ أُخَرَ ۚ وَعَلَى ٱلَّذِينَ يُطِيقُونَهُۥ فِدْيَةٌۭ طَعَامُ مِسْكِينٍۢ ۖ فَمَن تَطَوَّعَ خَيْرًۭا فَهُوَ خَيْرٌۭ لَّهُۥ ۚ وَأَن تَصُومُوا۟ خَيْرٌۭ لَّكُمْ ۖ إِن كُنتُمْ تَعْلَمُونَ ﴿١٨٤﴾

(Fast) a certain number of days; and (for) him who is sick among you, or on a journey, (the same) number of other days; and for those who can afford it there is a ransom: the feeding of a man in need - but whoso doeth good of his own accord, it is better for him: and that ye fast is better for you if ye did but know -