Wages (Kitab Al-Ijarah)
Dawud :: Book 23 : Hadith 3533
Narrated Abdullah ibn Amr ibn al-'As:
The Prophet (peace_be_upon_him) said: The similitude of the one who takes back what he gifted is like that of a dog which vomits and then it eats vomit. When a donor seeks to take back (his gift), it should be made known and he informed why he sought to take it back. Then whatever he donated should be returned to him.