The Book of Zakat (Kitab Al-Zakat)
Muslim :: Book 5 : Hadith 2236
Umair, the freed slave of Abi'l-Lahm reported: 1 was the slave (of Abi'l-Lahm). I asked the Messenger of Allah (may peace be upon him) if I could give some charity out of my master's wealth. He said: Yes, and the reward is half and half between you two.