Sahih Muslim
The Book of Zakat (Kitab Al-Zakat)
Book Number: 005 / Hadith Number: 2231
Abu Musa reported Allah's Apostle (may peace be upon him) as saying: The honest Muslim trustee who spends (sometimes he said" who gives" ) what he is commanded to do and he gives that in full with his heart overflowing with cheerfulness and he gives it to one to whom he is ordered, he is one of the givers of charity.