Musnad Abu Ya'la al-Mawsili 155:240

Abu Khaythama narrated to us, Jarir narrated to us, from 'Umarah ibn al-Qa'qa', from Abu Zur'ah, from Abu Hurayrah, who said: A man came to the Messenger of Allah (may Allah bless him and grant him peace) and said: "O Messenger of Allah, which charity is the greatest?" He said: "That you give charity while you are healthy and stingy, fearing poverty and hoping for life. 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."