The Book of Gifts
Ṣaḥīḥ Muslim 4170
مَثَلُ الَّذِي يَرْجِعُ فِي صَدَقَتِهِ كَمَثَلِ الْكَلْبِ يَقِيءُ ثُمَّ يَعُودُ فِي قَيْئِهِ فَيَأْكُلُهُ
mathalu adh-dhī yarjiʿu fī ṣadaqatihi kamathali al-kalbi yaqīʾu thumma yaʿūdu fī qayʾihi fayaʾkuluhu
Transliteration generated from the Arabic vowel marks
The full narration
Ibn 'Abbas (Allah be pleased with them) reported Allah's Apostle (ﷺ) having said this:He who gets back his charity is like a dog which vomits, and then returns to that and eats it
Source
Ṣaḥīḥ Muslim · 4170
Ṣaḥīḥ