Abdullah bin Hubayrah said that Sayyiduna Ali (may Allah be pleased with him) gave a judgement concerning a slave who was married to a free woman; she bore children, who were freed because of their mother's freedom, and then their father was freed. He (may Allah be pleased with him) said: "Their wala belongs to the agnatic relatives ('asabah) of their father."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الولاء / 21522