The Book of Zakat (Kitab Al-Zakat)
Muslim :: Book 5 : Hadith 2205
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: There is never a day wherein servants (of God) get up at morn, but are not visited by two angels. One of them says: 0 Allah, give him more who spends (for the sake of Allah), and the other says: 0 Allah, bring destruction to one who withholds.