The Book of Gifts
Ṣaḥīḥ Muslim 4173
إِنَّمَا مَثَلُ الَّذِي يَتَصَدَّقُ بِصَدَقَةٍ ثُمَّ يَعُودُ فِي صَدَقَتِهِ كَمَثَلِ الْكَلْبِ يَقِيءُ ثُمَّ يَأْكُلُ قَيْأَهُ
innamā mathalu adh-dhī yataṣaddaqu biṣadaqatin thumma yaʿūdu fī ṣadaqatihi kamathali al-kalbi yaqīʾu thumma yaʾkulu qayʾah
Transliteration generated from the Arabic vowel marks
The full narration
Ibn Abbas (Allah be pleased with them) reported:I heard Allah's Messenger (ﷺ) say: The similitude of one who gives a charity and then gets it back is like that of a dog which vomits and then eats its vomit
Source
Ṣaḥīḥ Muslim · 4173
Ṣaḥīḥ