Musnad Ahmad 30:2001

Abu Ahmad narrated to us, Mu'aqil—meaning Ibn Ubayd Allah—narrated to us, from 'Ata, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Charity is [given] out of surplus wealth, and begin with those whom you support. And the upper hand is better than the lower hand."