What does the Quran say about fasting and Ramadan?

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

O you who have believed, decreed upon you is fasting as it was decreed upon those before you that you may become righteous -

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

[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.

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

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. So whoever sights [the new moon of] the month, let him fast it; and whoever is ill or on a journey - then an equal number of other days. Allah intends for you ease and does not intend for you hardship and [wants] for you to complete the period and to glorify Allah for that [to] which He has guided you; and perhaps you will be grateful.

وَإِذَا سَأَلَكَ عِبَادِى عَنِّى فَإِنِّى قَرِيبٌ ۖ أُجِيبُ دَعْوَةَ ٱلدَّاعِ إِذَا دَعَانِ ۖ فَلْيَسْتَجِيبُوا۟ لِى وَلْيُؤْمِنُوا۟ بِى لَعَلَّهُمْ يَرْشُدُونَ

And when My servants ask you, [O Muhammad], concerning Me - indeed I am near. I respond to the invocation of the supplicant when he calls upon Me. So let them respond to Me [by obedience] and believe in Me that they may be [rightly] guided.

أُحِلَّ لَكُمْ لَيْلَةَ ٱلصِّيَامِ ٱلرَّفَثُ إِلَىٰ نِسَآئِكُمْ ۚ هُنَّ لِبَاسٌۭ لَّكُمْ وَأَنتُمْ لِبَاسٌۭ لَّهُنَّ ۗ عَلِمَ ٱللَّهُ أَنَّكُمْ كُنتُمْ تَخْتَانُونَ أَنفُسَكُمْ فَتَابَ عَلَيْكُمْ وَعَفَا عَنكُمْ ۖ فَٱلْـَٰٔنَ بَٰشِرُوهُنَّ وَٱبْتَغُوا۟ مَا كَتَبَ ٱللَّهُ لَكُمْ ۚ وَكُلُوا۟ وَٱشْرَبُوا۟ حَتَّىٰ يَتَبَيَّنَ لَكُمُ ٱلْخَيْطُ ٱلْأَبْيَضُ مِنَ ٱلْخَيْطِ ٱلْأَسْوَدِ مِنَ ٱلْفَجْرِ ۖ ثُمَّ أَتِمُّوا۟ ٱلصِّيَامَ إِلَى ٱلَّيْلِ ۚ وَلَا تُبَٰشِرُوهُنَّ وَأَنتُمْ عَٰكِفُونَ فِى ٱلْمَسَٰجِدِ ۗ تِلْكَ حُدُودُ ٱللَّهِ فَلَا تَقْرَبُوهَا ۗ كَذَٰلِكَ يُبَيِّنُ ٱللَّهُ ءَايَٰتِهِۦ لِلنَّاسِ لَعَلَّهُمْ يَتَّقُونَ

It has been made permissible for you the night preceding fasting to go to your wives [for sexual relations]. They are clothing for you and you are clothing for them. Allah knows that you used to deceive yourselves, so He accepted your repentance and forgave you. So now, have relations with them and seek that which Allah has decreed for you. And eat and drink until the white thread of dawn becomes distinct to you from the black thread [of night]. Then complete the fast until the sunset. And do not have relations with them as long as you are staying for worship in the mosques. These are the limits [set by] Allah, so do not approach them. Thus does Allah make clear His ordinances to the people that they may become righteous.

۞ يَٰبَنِىٓ ءَادَمَ خُذُوا۟ زِينَتَكُمْ عِندَ كُلِّ مَسْجِدٍۢ وَكُلُوا۟ وَٱشْرَبُوا۟ وَلَا تُسْرِفُوٓا۟ ۚ إِنَّهُۥ لَا يُحِبُّ ٱلْمُسْرِفِينَ

O children of Adam, take your adornment at every masjid, and eat and drink, but be not excessive. Indeed, He likes not those who commit excess.

وَمِنَ ٱلَّيْلِ فَتَهَجَّدْ بِهِۦ نَافِلَةًۭ لَّكَ عَسَىٰٓ أَن يَبْعَثَكَ رَبُّكَ مَقَامًۭا مَّحْمُودًۭا

And from [part of] the night, pray with it as additional [worship] for you; it is expected that your Lord will resurrect you to a praised station.

تَتَجَافَىٰ جُنُوبُهُمْ عَنِ ٱلْمَضَاجِعِ يَدْعُونَ رَبَّهُمْ خَوْفًۭا وَطَمَعًۭا وَمِمَّا رَزَقْنَٰهُمْ يُنفِقُونَ

They arise from [their] beds; they supplicate their Lord in fear and aspiration, and from what We have provided them, they spend.

إِنَّآ أَنزَلْنَٰهُ فِى لَيْلَةٍۢ مُّبَٰرَكَةٍ ۚ إِنَّا كُنَّا مُنذِرِينَ

Indeed, We sent it down during a blessed night. Indeed, We were to warn [mankind].

فِيهَا يُفْرَقُ كُلُّ أَمْرٍ حَكِيمٍ

On that night is made distinct every precise matter -

كَانُوا۟ قَلِيلًۭا مِّنَ ٱلَّيْلِ مَا يَهْجَعُونَ

They used to sleep but little of the night,

وَبِٱلْأَسْحَارِ هُمْ يَسْتَغْفِرُونَ

And in the hours before dawn they would ask forgiveness,

أَوْ زِدْ عَلَيْهِ وَرَتِّلِ ٱلْقُرْءَانَ تَرْتِيلًا

Or add to it, and recite the Qur'an with measured recitation.

إِنَّ نَاشِئَةَ ٱلَّيْلِ هِىَ أَشَدُّ وَطْـًۭٔا وَأَقْوَمُ قِيلًا

Indeed, the hours of the night are more effective for concurrence [of heart and tongue] and more suitable for words.

بِّسْمِ ٱللَّهِ ٱلرَّحْمَٰنِ ٱلرَّحِيمِ إِنَّآ أَنزَلْنَٰهُ فِى لَيْلَةِ ٱلْقَدْرِ

Indeed, We sent the Qur'an down during the Night of Decree.

وَمَآ أَدْرَىٰكَ مَا لَيْلَةُ ٱلْقَدْرِ

And what can make you know what is the Night of Decree?

لَيْلَةُ ٱلْقَدْرِ خَيْرٌۭ مِّنْ أَلْفِ شَهْرٍۢ

The Night of Decree is better than a thousand months.

تَنَزَّلُ ٱلْمَلَٰٓئِكَةُ وَٱلرُّوحُ فِيهَا بِإِذْنِ رَبِّهِم مِّن كُلِّ أَمْرٍۢ

The angels and the Spirit descend therein by permission of their Lord for every matter.

سَلَٰمٌ هِىَ حَتَّىٰ مَطْلَعِ ٱلْفَجْرِ

Peace it is until the emergence of dawn.