Al-Baqarah 2:184
أَيَّامًا مَّعْدُودَاتٍ ۚ فَمَن كَانَ مِنكُم مَّرِيضًا أَوْ عَلَىٰ سَفَرٍ فَعِدَّةٌ مِّنْ أَيَّامٍ أُخَرَ ۚ وَعَلَى الَّذِينَ يُطِيقُونَهُ فِدْيَةٌ طَعَامُ مِسْكِينٍ ۖ فَمَن تَطَوَّعَ خَيْرًا فَهُوَ خَيْرٌ لَّهُ ۚ وَأَن تَصُومُوا خَيْرٌ لَّكُمْ ۖ إِن كُنتُمْ تَعْلَمُونَ ١٨٤
Ayyaman maAAdoodatin faman kana minkum mareedan aw AAala safarin faAAiddatun min ayyamin okhara waAAala allatheena yuteeqoonahu fidyatun taAAamu miskeenin faman tatawwaAAa khayran fahuwa khayrun lahu waan tasoomoo khayrun lakum in kuntum taAAlamoona
for days numbered; and if any of you be sick, or if he be on a journey, then a number of other days; and for those who are able to fast, a redemption by feeding a poor man. Yet better it is for him who volunteers good, and that you should fast is better for you, if you but know; (2:184)