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كتاب الزكاة
24  
Obligatory Charity Tax (Zakat)
(16)
Chapter: To give objects of charity with the right hand
(16)
باب الصَّدَقَةِ بِالْيَمِينِ
Sahih al-Bukhari 1424

Narrated 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."

حَدَّثَنَا عَلِيُّ بْنُ الْجَعْدِ، أَخْبَرَنَا شُعْبَةُ، قَالَ أَخْبَرَنِي مَعْبَدُ بْنُ خَالِدٍ، قَالَ سَمِعْتُ حَارِثَةَ بْنَ وَهْبٍ الْخُزَاعِيَّ ـ رضى الله عنه ـ يَقُولُ سَمِعْتُ النَّبِيَّ صلى الله عليه وسلم يَقُولُ ‏ "‏ تَصَدَّقُوا، فَسَيَأْتِي عَلَيْكُمْ زَمَانٌ يَمْشِي الرَّجُلُ بِصَدَقَتِهِ فَيَقُولُ الرَّجُلُ لَوْ جِئْتَ بِهَا بِالأَمْسِ لَقَبِلْتُهَا مِنْكَ، فَأَمَّا الْيَوْمَ فَلاَ حَاجَةَ لِي فِيهَا ‏"‏‏.‏
Reference : Sahih al-Bukhari 1424
In-book reference : Book 24, Hadith 28
USC-MSA web (English) reference : Vol. 2, Book 24, Hadith 505
  (deprecated numbering scheme)