Sahih Muslim 4165
صحيح مسلم#4165SahihZaid b. Aslam reported on the authority of his father that 'Umar (Allah be pleased with him) donated a horse in the path of Allah. He found that it had languished in the hand of its possessor, and he was a man of meagre resources He (Hadrat 'Umar) intended to buy it. He came to Allah's Messenger (ﷺ) and made a mention of that to him, whereupon he said:Don't buy that even if you get it for a dirham for he who gets back the charity is like a dog which swallows its vomit
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 24:3