Musannaf Ibn Abi Shayba 13:1553

Abu Bakr narrated to us, he said: Ibn Abi Za’idah narrated to us, from Isma’il, from al-Sha’bi, who said: I said to him: "Shurayh used to judge regarding the *mukātab* (an enslaved person with a contract of manumission) who dies and leaves behind wealth and children: that his masters should be paid what remains of his *kitābah* (contract), and what remains should be returned to his children." He said: "Indeed, Shurayh used to judge regarding it according to the judgment of ‘Abdullah."