Yazid bin Abi Habib narrated from Ibn Shihab, from Abu Salamah, from Jabir, that the Messenger of Allah ruled concerning 'Umra -when a man gives a gift to another man, and his descendants, but stipulates that if something happens to you and your descendants, then it will belong to me and my descendants- "It belongs to the one to whom it was given, and to his descendants." (Using translation from Nasāʾī 3749)
أَنَّ رَسُولَ اللهِ ﷺ «قَضَى بِالْعُمْرَى أَنْ يَهَبَ الرَّجُلُ لِلرَّجُلِ وَلِعَقِبِهِ الْهِبَةَ وَيَسْتَثْنِي إِنْ حَدَثَ بِكَ حَدَثٌ وَبِعَقِبِكَ فَهُوَ إِلَيَّ وَإِلَى عَقِبِي إِنَّهَا لِمَنْ أُعْطِيَهَا وَلِعَقِبِهِ»