Sahih Muslim
The Book of Zakat (Kitab Al-Zakat)
Book Number: 005 / Hadith Number: 2182
Khaithama reported: While we were sitting in the company of 'Abdullah b. 'Umar there came in his steward. He (Ibn 'Umar) said: Have you supplied the provision to the slaves? He said: No. Upon this he said: Go and give (the provision) to them, for the Messenger of Allah (may peace be upon him) has said: This sin is enough for a man that he withholds the subsistence from one whose master he is.