Mishkat al-Masabih 11 Business Transactions كتاب البيوع 248

وَعَنْهُ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «الْعُمْرَى جَائِزَةٌ لِأَهْلِهَا وَالرُّقْبَى جَائِزَةٌ لِأَهْلِهَا» . رَوَاهُ أَحْمد وَالتِّرْمِذِيّ وَأَبُو دَاوُد

He reported the Prophet as saying, “Both life-tenancy and giving property which goes to the survivor are a gift which belongs to those who receive it.” Ahmad, Tirmidhi and Abu Dawud transmitted it.