Muwatta Malik, Book 38, Hadith 1469 (In-Book) ⓘ

Malik related to me from Rabia ibn Abi Abd ar-Rahman that a man in the time of Aban ibn Uthman's amirate freed all of his slaves and did not have other property than them. Aban ibn Uthman took charge of the slaves and they were divided into three groups. Then he drew lots on the basis that which ever group drew the dead man's arrow would be free. The arrow fell to one of the thirds, and that third was freed.

وَحَدَّثَنِي مَالِكٌ، عَنْ رَبِيعَةَ بْنِ أَبِي عَبْدِ الرَّحْمَنِ، أَنَّ رَجُلاً، فِي إِمَارَةِ أَبَانَ بْنِ عُثْمَانَ أَعْتَقَ رَقِيقًا لَهُ كُلَّهُمْ جَمِيعًا وَلَمْ يَكُنْ لَهُ مَالٌ غَيْرُهُمْ فَأَمَرَ أَبَانُ بْنُ عُثْمَانَ بِتِلْكَ الرَّقِيقِ فَقُسِمَتْ أَثْلاَثًا ثُمَّ أَسْهَمَ عَلَى أَيِّهِمْ يَخْرُجُ سَهْمُ الْمَيِّتِ فَيَعْتِقُونَ فَوَقَعَ السَّهْمُ عَلَى أَحَدِ الأَثْلاَثِ فَعَتَقَ الثُّلُثُ الَّذِي وَقَعَ عَلَيْهِ السَّهْمُ ‏.‏