Sahih Bukhari Volume 3, Book 34, Hadith 2142

حَدَّثَنَا بِشْرُ بْنُ مُحَمَّدٍ، أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا الْحُسَيْنُ الْمُكْتِبُ، عَنْ عَطَاءِ بْنِ أَبِي رَبَاحٍ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ ـ رضى الله عنهما ـ أَنَّ رَجُلاً أَعْتَقَ غُلاَمًا لَهُ عَنْ دُبُرٍ، فَاحْتَاجَ فَأَخَذَهُ النَّبِيُّ صلى الله عليه وسلم فَقَالَ ‏"‏ مَنْ يَشْتَرِيهِ مِنِّي ‏"‏ فَاشْتَرَاهُ نُعَيْمُ بْنُ عَبْدِ اللَّهِ بِكَذَا وَكَذَا، فَدَفَعَهُ إِلَيْهِ‏.‏

Narrated By Jabir bin Abdullah : A man decided that a slave of his would be manumitted after his death and later on he was in need of money, so the Prophet took the slave and said, "Who will buy this slave from me?" Nu'aim bin 'Abdullah bought him for such and such price and the Prophet gave him the slave.