Sahih Bukhari Volume 2, Book 24, Hadith Number 505.

Narated By Haritha bin Wahab Al-Khuza’i : I heard the Prophet (p.b.u.h) saying, “(O people!) Give in charity (for Allah’s cause) because a time will come when a person will carry his object of charity from place to place (and he will not find any person to take it) and any person whom he shall request to take it, I will reply, ‘If you had brought it yesterday I would have taken it, but today I am not in need of it.”