Allah says in Quran:
شَهۡرُ رَمَضَانَ ٱلَّذِيٓ أُنزِلَ فِيهِ ٱلۡقُرۡءَانُ هُدٗى لِّلنَّاسِ وَبَيِّنَٰتٖ مِّنَ ٱلۡهُدَىٰ وَٱلۡفُرۡقَانِۚ فَمَن شَهِدَ مِنكُمُ ٱلشَّهۡرَ فَلۡيَصُمۡهُۖ وَمَن كَانَ مَرِيضًا أَوۡ عَلَىٰ سَفَرٖ فَعِدَّةٞ مِّنۡ أَيَّامٍ أُخَرَۗ يُرِيدُ ٱللَّهُ بِكُمُ ٱلۡيُسۡرَ وَلَا يُرِيدُ بِكُمُ ٱلۡعُسۡرَ وَلِتُكۡمِلُواْ ٱلۡعِدَّةَ وَلِتُكَبِّرُواْ ٱللَّهَ عَلَىٰ مَا هَدَىٰكُمۡ وَلَعَلَّكُمۡ تَشۡكُرُونَ
The month of Ramaḍan in which was revealed the Qur’ān, 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 Ramaḍan i.e. is present at his home), he must observe Ṣaum (fast) that month, and whoever is ill or on a journey, the same number [of days which one did not observe Ṣaum (fast) must be made up] from other days. Allāh intends for you ease, and He does not want to make things difficult for you. (He wants that you) must complete the same number (of days), and that you must magnify Allāh [i.e. to say Takbīr (Allāhu Akbar; Allāh is the Most Great)] for having guided you, so that you may be grateful to Him.
Surah Al-Baqara: Ayah 185
- May Allah enable us to reach it. May Allah enable us to do it in all.