(This is) by way of deduction from the preceding evidence on the establishment of wala' for the one who frees, and on the basis that wala' has been likened to lineage; and some of our companions have argued on this point.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الولاء / Q21488
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "I am closer to the believers than their own selves. Whoever dies and leaves wealth, it will be distributed among his 'asabah (i.e. his relatives), and whoever leaves a debt or helpless dependents (daya'), I am responsible for him."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الولاء / 21488
Abdullah bin Shaddad (may Allah have mercy on him) said: The daughter of Sayyiduna Hamzah bin Abd al-Muttalib (may Allah be pleased with him) had a slave. The daughter of Sayyiduna Hamzah (may Allah be pleased with him) freed the slave, and then the slave died. He left a daughter and his former mistress who had freed him, the daughter of Sayyiduna Hamzah (may Allah be pleased with him). The dispute was brought to the Prophet (peace and blessings be upon him), and the Prophet (peace and blessings be upon him) gave each of them half.
This is mursal; it has also been narrated mursal through other routes, some of which strengthen others.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الولاء / 21490