Hadith 8:248
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.
وَعَنْهُ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «الْعُمْرَى جَائِزَةٌ لِأَهْلِهَا وَالرُّقْبَى جَائِزَةٌ لِأَهْلِهَا» . رَوَاهُ أَحْمد وَالتِّرْمِذِيّ وَأَبُو دَاوُد
Original Reference: Mishkat al-Masabih 3014