It is narrated from Sayyiduna Ibn Umar and Sayyiduna Ibn Abbas (may Allah be pleased with them) that the Messenger of Allah (peace and blessings be upon him) said: "It is not lawful for a person to give a gift to someone and then ask for it back, except for a father who gives something to his son and then takes it back; he is exempted. Whoever gives a gift to someone and then asks for it back, his example is like that of a dog who eats something, and when he is full, he vomits it out and then starts licking his own vomit."