Musnad Ahmad 27:1044

Muhammad ibn Ja'far narrated to us, Husayn al-Mu'allim narrated to us, from 'Amr ibn Shu'ayb, from Tawus, from Ibn 'Umar and Ibn 'Abbas, from the Prophet, peace and blessings of Allah be upon him, that he said: "It is not lawful for a man to give a gift and then take it back, except for a father regarding what he gives to his child. And the likeness of one who gives a gift and then takes it back is like the likeness of a dog that eats until, when it is full, it vomits, and then returns to its vomit."