al-Mughira bin Maqsam المغيرة بن مقسم · The Chapters on Gifts

“I heard the Messenger of Allah (ﷺ) say: 'Whoever gives a lifelong grant to a man, it belongs to him (the recipient) and to his heirs. His (the giver's) words put an end to his right to it, and it belongs to the one to whom it was given for life and to his heirs.”