Sayyiduna Imran bin Husayn (may Allah be pleased with him) said: A man from the Ansar died and left six slaves, and he had no wealth other than them; he freed all of them at the time of his death. The matter was referred to the Prophet (peace and blessings be upon him), "so he (peace and blessings be upon him) divided them into three parts, then cast lots between them, freed one third and kept two thirds in slavery."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15549