أَيَّامًا مَّعْدُودَاتٍ فَمَن كَانَ مِنكُم مَّرِيضًا أَوْ عَلَى سَفَرٍ فَعِدَّةٌ مِّنْ أَيَّامٍ أُخَرَ وَعَلَى الَّذِينَ يُطِيقُونَهُ فِدْيَةٌ طَعَامُ مِسْكِينٍ فَمَن تَطَوَّعَ خَيْرًا فَهُوَ خَيْرٌ لَّهُ وَأَن تَصُومُواْ خَيْرٌ لَّكُمْ إِن كُنتُمْ تَعْلَمُونَ
﴿١٨٤﴾
سورة البقرة
(2/184) For a fixed number of days; but if any of you is ill or on a journey, then (he shall fast) a (like) number of other days; and those who are not able to do it (fasting, because of old age or an illness that is not recoverable) may effect a redemption by feeding a poor (night and day); so whosoever does good (increases his fasting or his redemption) it is better for him. And fasting is better for you if you only knew.
Surah Al-Baqarah