For he conferred a grant and as such it becomes heritage. and the right of inheritance abrogated his condition.
Sahih Muslim Book 24, Hadith 30
← Previous Hadith The Umra for which Allah's Messenger (ﷺ) gave sanction that a person way say: This (property) is for you and for your descendants. And when he said: That is for you as long as you live, then it will return to its owner (after the death of the donee). Ma'mar said: Zuhri used to give religious verdict according to this.

Sahih Muslim Book 24, Hadith 29 Next Hadith → Life grant is for one upon whom it is bestowed.

Sahih Muslim Book 24, Hadith 31