(1) باب كَرَاهَةِ شِرَاءِ الإِنْسَانِ مَا تَصَدَّقَ بِهِ مِمَّنْ تَصَدَّقَ عَلَيْهِ
Umar b. Khattab (Allah be pleased with him) reported:
I donated a pedigree horse in the path of Allah. Its possessor made it languish. I thought that he would sell it at a cheap price. I asked Allah's Messenger (ﷺ) about it, whereupon he said: Don't buy it and do not get back your charity, for one who gets back the charity is like a dog who swallows its vomit.
Reference: Sahih Muslim 1620 a
In-book reference: Book 24, Hadith 1
USC-MSA web (English) reference(deprecated numbering scheme): Book 12, Hadith 3949