Those who spend their wealth in the way of Allah and do not follow up their spending by stressing their benevolence and causing hurt, will find their reward secure with their Lord. They have no cause for fear and grief. To speak a kind word and to forgive people's faults is better than charity followed by hurt. Allah is All-Sufficient, All-Forbearing Believers! Do not nullify your acts of charity by stressing your benevolence and causing hurt as does he who spends his wealth only to be seen by men and does not believe in Allah and the Last Day. The example of his spending is that of a rock with a thin coating of earth upon it: when a heavy rain smites it, the earth is washed away, leaving the rock bare; such people derive no gain from their acts of charity. Allah does not set the deniers of the Truth on the right way. (2:262 - 264)
Narrated by: Abdullah bin 'Umar
The Prophet ordered (Muslims) to give one Sa' of dates or one Sa' of barley as Zakat-ul-Fitr. The people rewarded two Mudds of wheat as equal to that.