Sura al-Baqara 2:185

شَهْرُ رَمَضَانَ ٱلَّذِىٓ أُنزِلَ فِيهِ ٱلْقُرْءَانُ هُدًى لِّلنَّاسِ وَبَيِّنَٰتٍ مِّنَ ٱلْهُدَىٰ وَٱلْفُرْقَانِ فَمَن شَهِدَ مِنكُمُ ٱلشَّهْرَ فَلْيَصُمْهُ وَمَن كَانَ مَرِيضًا أَوْ عَلَىٰ سَفَرٍ فَعِدَّةٌ مِّنْ أَيَّامٍ أُخَرَ يُرِيدُ ٱللَّـهُ بِكُمُ ٱلْيُسْرَ وَلَا يُرِيدُ بِكُمُ ٱلْعُسْرَ وَلِتُكْمِلُوا۟ ٱلْعِدَّةَ وَلِتُكَبِّرُوا۟ ٱللَّـهَ عَلَىٰ مَا هَدَىٰكُمْ وَلَعَلَّكُمْ تَشْكُرُونَ

shahru ramaḍāna alladhī unzila fīhi l-qurʾānu hudan lil-nāsi wa-bayyinātin mina l-hudā wa-l-furqāni fa-man shahida minkumu l-shahra fa-l-yaṣumhu wa-man kāna marīḍan aw ʿalā safarin faʿiddatun min ayyāmin ukhara yurīdu allāhu bikumu l-yusra wa-lā yurīdu bikumu l-ʿusra wa-li-tukmilū l-ʿiddata wa-li-tukabbirū allāha ʿalā mā hadākum wa-la-ʿallakum tashkurūna

Ramadhan is the (month) in which was sent down the Qur'an, as a guide to mankind, also clear (Signs) for guidance and judgment (Between right and wrong). So every one of you who is present (at his home) during that month should spend it in fasting, but if any one is ill, or on a journey, the prescribed period (Should be made up) by days later. Allah intends every facility for you; He does not want to put to difficulties. (He wants you) to complete the prescribed period, and to glorify Him in that He has guided you; and perchance ye shall be grateful.