Musnad Ahmad 30:289

Jarir ibn Abd al-Hamid narrated to us, from Umarah ibn al-Qa'qa', from Abu Zur'ah, from Abu Hurayrah, who said: The Messenger of Allah, peace and blessings of Allah be upon him, was asked: "Which charity is best?" He said: "You shall be informed: That you give charity while you are healthy and stingy, hoping for longevity and fearing poverty. And do not delay until, when it reaches the throat, you say: 'For so-and-so is such-and-such, and for so-and-so is such-and-such,' when it has already become for so-and-so."