Sahih Bukhari Volume 2, Book 24, Hadith 1412

حَدَّثَنَا آدَمُ، حَدَّثَنَا شُعْبَةُ، حَدَّثَنَا مَعْبَدُ بْنُ خَالِدٍ، قَالَ سَمِعْتُ حَارِثَةَ بْنَ وَهْبٍ، قَالَ سَمِعْتُ النَّبِيَّ صلى الله عليه وسلم يَقُولُ ‏"‏ تَصَدَّقُوا فَإِنَّهُ يَأْتِي عَلَيْكُمْ زَمَانٌ يَمْشِي الرَّجُلُ بِصَدَقَتِهِ، فَلاَ يَجِدُ مَنْ يَقْبَلُهَا يَقُولُ الرَّجُلُ لَوْ جِئْتَ بِهَا بِالأَمْسِ لَقَبِلْتُهَا، فَأَمَّا الْيَوْمَ فَلاَ حَاجَةَ لِي بِهَا ‏"‏‏

Narrated By Haritha bin Wahab : I heard the Prophet saying, "O people! Give in charity as a time will come upon you when a person will wander about with his object of charity and will not find anybody to accept it, and one (who will be requested to take it) will say, "If you had brought it yesterday, would have taken it, but to-day I am not in need of it."