(11) CHAPTER. The Statement of Allah: “Those who defame such of the believers who give charity (in Allah's Cause) voluntarily... (V.9:79)
Narrated Abu Musud: When we were ordered to give alms, we began to work as porters (to earn something we could give in charity). Abu Uqail came with one half of a Sa (special measure for food grains) and another person brought more than he did. So the hypocrites said, Allah is not in need of the alms of this (i.e. 'Uqail); and this other person did not give alms but for showing off. Then Allah revealed:-- 'Those who criticize such of the Believers who give charity voluntarily and those who could not find to give in charity except what is available to them.' (9.79)
Narrated Shaqiq: Abu Mas`ud Al-Ansari said, Allah's Messenger , used to order us to give alms. So one of us would exert himself to earn one Mud (special measure of wheat or dates, etc.,) to give in charity; while today one of us may have one hundred thousand. Shaqiq said: As if Abu Masud referred to himself.