Abu al-Malih (may Allah have mercy on him) narrates from his father that a man freed his share of a slave. This was mentioned to the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Allah has no partner." Ibn Kathir (may Allah have mercy on him) added some words: that the Prophet (peace and blessings be upon him) validated his freeing (of the slave).
The Shaykh (may Allah have mercy on him) said: It is possible that this refers to one who freed his share of a slave jointly owned between him and someone else, and another meaning is also possible.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21316
Abu al-Malih (may Allah have mercy on him) said that a man from his people freed one third of his slave. The Prophet (peace and blessings be upon him) was informed, and he (peace and blessings be upon him) said: "He is completely free; Allah has no partner."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21317
Khalid bin Salamah al-Makhzumi (may Allah have mercy on him) narrates that a man came to Sayyiduna Umar (may Allah be pleased with him) at Arafah and said: "I set free my share of this slave." He said: "Set him free entirely, for Allah has no partner."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21318
Isma'il bin Umayyah narrates from his father, and he from his grandfather, that they had a slave named Tahman or Dhakwan. Their grandfather set half of him free. The slave came and informed the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "You are free to the extent that you have been freed, and the remaining part is enslaved." He continued to serve his master until he died.
Only Umar bin Hawshab narrated it. Isma'il is Ibn Umayyah bin Amr bin Sa'id bin al-As, and Amr bin Sa'id was not a Companion.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21319
Alqamah bin Abdullah al-Muzani (may Allah have mercy on him) narrates from his father (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A man may free as much of his slave as he wishes: a third, a quarter or a fifth. There is no compulsion between Allah and that servant."
(b) Abu al-Walid (may Allah have mercy on him) said: Whatever share the deceased has freed, nothing else will cancel it; that much will be free.
This is a good interpretation, except that this Muhammad bin Fada' is da'if (weak) and is not used as proof; Yahya bin Ma'in, Sulayman bin Harb and Abu Abd al-Rahman al-Nasa'i (may Allah have mercy on them) criticised him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21320
Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) says: When a man owns a slave and frees half of him, then only as much is freed as he has freed.
This is munqati' (its chain is broken).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21321