Hadith
أَخْبَرَنَا أَبُو دَاوُدَ، سُلَيْمَانُ بْنُ سَيْفٍ قَالَ حَدَّثَنَا يَعْقُوبُ، قَالَ حَدَّثَنَا أَبِي، عَنْ صَالِحٍ، عَنِ ابْنِ شِهَابٍ، أَنَّ أَبَا سَلَمَةَ، أَخْبَرَهُ عَنْ جَابِرٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " أَيُّمَا رَجُلٍ أَعْمَرَ رَجُلاً عُمْرَى لَهُ وَلِعَقِبِهِ قَالَ قَدْ أَعْطَيْتُكَهَا وَعَقِبَكَ مَا بَقِيَ مِنْكُمْ أَحَدٌ فَإِنَّهَا لِمَنْ أُعْطِيَهَا وَإِنَّهَا لاَ تَرْجِعُ إِلَى صَاحِبِهَا مِنْ أَجْلِ أَنَّهُ أَعْطَاهَا عَطَاءً وَقَعَتْ فِيهِ الْمَوَارِيثُ " .
Salih narrated from Ibn Shihab, that Abu Salamah informed him from Jabir, that the Messenger of Allah said:"Any man who gives a lifelong gift to another man, it belongs to him (the recipient) and his descendants. He said: 'I have given it to you and to your descendants so long as any of you are still alive.' So it belongs to the one to whom it was given, and it cannot revert to the first owner, since he has given it as a gift, and as such, it becomes subject to the same ruling as the estate
Sahih · Abu Ghuddah
Sunan an-Nasa'i 3748 ·Book 34, Hadith 30·Also available on sunnah.com·