Manumission of Slaves
حَدَّثَنَا آدَمُ بْنُ أَبِي إِيَاسٍ، حَدَّثَنَا شُعْبَةُ، حَدَّثَنَا عَمْرُو بْنُ دِينَارٍ، سَمِعْتُ جَابِرَ بْنَ عَبْدِ اللَّهِ ـ رضى الله عنهما ـ قَالَ أَعْتَقَ رَجُلٌ مِنَّا عَبْدًا لَهُ عَنْ دُبُرٍ، فَدَعَا النَّبِيُّ صلى الله عليه وسلم بِهِ فَبَاعَهُ. قَالَ جَابِرٌ مَاتَ الْغُلاَمُ عَامَ أَوَّلَ.Narrated Jabir bin `Abdullah:A man amongst us declared that his slave would be freed after his death. The Prophet (ﷺ) called for that slave and sold him. The slave died the same year
From Sahih al-Bukhari, whose reports the scholars accept as authentic.