Musannaf Ibn Abi Shayba 20:39

Abu Bakr narrated to us, he said: Yahya ibn Adam narrated to us, he said: Ibn Abi Dhi'b narrated to us, from Ibn Shihab, from Abu Salamah, from Jabir ibn Abdullah, who said: The Messenger of Allah (may Allah bless him and grant him peace) decreed regarding the *'umra* (life-gift) that it belongs to the one to whom it was given and to his descendants, definitively. The giver has no condition in it, nor any reservation.