Shu'bah bin al-Hajjaj شعبة بن الحجاج · The Book of 'Umra

"'Umra (a gift given for life) belongs to the heir."

"Any man who is given a gift on the basis of 'Umra, it belongs to him and to his descendants. It belongs to the one to whom he gave it, and it cannot be taken back by the one who gave it, because he has given a gift, and it comes to the heirs of the one to whom it was given."

"Yahya narrated to us that Abu Salamah narrated to him, from Jabir bin 'Abdullah, from the Prophet of Allah who said: 'A lifelong gift belongs to the one to whom it was given.'"