At-Tawbah 9:79

ٱلَّذِينَ يَلْمِزُونَ ٱلْمُطَّوِّعِينَ مِنَ ٱلْمُؤْمِنِينَ فِى ٱلصَّدَقَٰتِ وَٱلَّذِينَ لَا يَجِدُونَ إِلَّا جُهْدَهُمْ فَيَسْخَرُونَ مِنْهُمْ ۙ سَخِرَ ٱللَّهُ مِنْهُمْ وَلَهُمْ عَذَابٌ أَلِيمٌ

Those who slander such of the believers as give themselves freely to (deeds of) charity, as well as such as can find nothing to give except the fruits of their labour,- and throw ridicule on them,- Allah will throw back their ridicule on them: and they shall have a grievous penalty.