Zakat (Kitab Al-Zakat)
Dawud :: Book 9 : Hadith 1687
Narrated AbuHurayrah:
The Prophet (peace_be_upon_him) commanded to give sadaqah. A man said: Apostle of Allah, I have a dinar. He said: Spend it on yourself. He again said: I have another. He said: Spend it on your children. He again said: I have another. He said: Spend it on your wife. He again said: I have another. He said: Spend it on your servant. He finally said: I have another. He replied: You know best (what to do with it).