(59) باب هَلْ يَشْتَرِي صَدَقَتَهُ
Narrated `Umar:
Once I gave a horse in Allah's Cause (in charity) but that person did not take care of it. I intended to buy it, as I thought he would sell it at a low price. So, I asked the Prophet (p.b.u.h) about it. He said, "Neither buy, nor take back your alms which you have given, even if the seller were willing to sell it for one Dirham, for he who takes back his alms is like the one who swallows his own vomit."
Reference: Sahih al-Bukhari 1490
In-book reference: Book 24, Hadith 91
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 24, Hadith 567