Narrated Abu Mas`ud:
When the verses of charity were revealed, we used to work as porters. A man came and distributed objects of charity in abundance. And they (the people) said, "He is showing off." And another man came and gave a Sa (a small measure of food grains); they said, "Allah is not in need of this small amount of charity." And then the Divine Inspiration came: "Those who criticize such of the believers who give in charity voluntarily and those who could not find to give in charity except what is available to them." (9:79).
حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، حَدَّثَنَا أَبُو النُّعْمَانِ الْحَكَمُ ـ هُوَ ابْنُ عَبْدِ اللَّهِ الْبَصْرِيُّ ـ حَدَّثَنَا شُعْبَةُ، عَنْ سُلَيْمَانَ، عَنْ أَبِي وَائِلٍ، عَنْ أَبِي مَسْعُودٍ ـ رضى الله عنه ـ قَالَ لَمَّا نَزَلَتْ آيَةُ الصَّدَقَةِ كُنَّا نُحَامِلُ، فَجَاءَ رَجُلٌ فَتَصَدَّقَ بِشَىْءٍ كَثِيرٍ فَقَالُوا مُرَائِي. وَجَاءَ رَجُلٌ فَتَصَدَّقَ بِصَاعٍ فَقَالُوا إِنَّ اللَّهَ لَغَنِيٌّ عَنْ صَاعِ هَذَا. فَنَزَلَتِ {الَّذِينَ يَلْمِزُونَ الْمُطَّوِّعِينَ مِنَ الْمُؤْمِنِينَ فِي الصَّدَقَاتِ وَالَّذِينَ لاَ يَجِدُونَ إِلاَّ جُهْدَهُمْ} الآيَةَ.