The Messenger of Allah ﷺ said, "Whenever a man grants a lifetime gift to another man and his descendants, saying, 'I have given it to you and your descendants for as long as any of you remain,' it belongs to the one to whom it was given. It does not return to the original owner, because he made a gift in which the rules of inheritance now apply."
أن رسول الله ﷺ قال: أيما رجل أعمر رجلا عمري له ولعقبه، فقال: قد أعطيتكها وعقبك ما بقى منكم أحد، فإنها لمن أعطيها، وإنها لا ترجع إلى صاحبها من أجل أنه أعطى عطاء وقعت فيه المواريث.
Muslim narrated it in the Book of Gifts (1625:22) from Abdul-Rahman bin Bishr Abdi, who said, "Abdul-Razzaq informed us, Ibn Jurayj informed us, Ibn Shihab informed me," regarding the "umra" gift and its rules, from the hadith of Abu Salama bin Abdul-Rahman, from Jabir bin Abdullah, and he narrated it.