2:158
إِنَّ ٱل صَّفَا وَ ٱلْ مَرْوَةَ مِن شَعَآئِرِ ٱللَّهِ فَ مَنْ حَجَّ ٱلْ بَيْتَ أَوِ ٱعْتَمَرَ فَ لَا جُنَاحَ عَلَيْ هِ أَن يَطَّوَّفَ بِ هِمَا وَ مَن تَطَوَّعَ خَيْرًا فَ إِنَّ ٱللَّهَ شَاكِرٌ عَلِيمٌ
Indeed, as-Safa and al-Marwah are among the symbols of Allah. So whoever makes Hajj to the House or performs 'umrah - there is no blame upon him for walking between them. And whoever volunteers good - then indeed, Allah is appreciative and Knowing.
2:184
أَيَّامًا مَّعْدُودَٰتٍ فَ مَن كَانَ مِن كُم مَّرِيضًا أَوْ عَلَىٰ سَفَرٍ فَ عِدَّةٌ مِّنْ أَيَّامٍ أُخَرَ وَ عَلَى ٱلَّذِينَ يُطِيقُ ونَ هُۥ فِدْيَةٌ طَعَامُ مِسْكِينٍ فَ مَن تَطَوَّعَ خَيْرًا فَ هُوَ خَيْرٌ لَّ هُۥ وَ أَن تَصُومُ وا۟ خَيْرٌ لَّ كُمْ إِن كُن تُمْ تَعْلَمُ ونَ
[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.
9:79
ٱلَّذِينَ يَلْمِزُ ونَ ٱلْ مُطَّوِّعِينَ مِنَ ٱلْ مُؤْمِنِينَ فِى ٱل صَّدَقَٰتِ وَ ٱلَّذِينَ لَا يَجِدُ ونَ إِلَّا جُهْدَ هُمْ فَ يَسْخَرُ ونَ مِنْ هُمْ سَخِرَ ٱللَّهُ مِنْ هُمْ وَ لَ هُمْ عَذَابٌ أَلِيمٌ
Those who criticize the contributors among the believers concerning [their] charities and [criticize] the ones who find nothing [to spend] except their effort, so they ridicule them - Allah will ridicule them, and they will have a painful punishment.