Musannaf Ibn Abi Shayba 9:1665

Ibn Abi Layla narrated to us, from Za’idah, from Mujalid, from al-Sha’bi, who said: A man came with a son of his whom he had acknowledged, then he wanted to disown him. They testified that he was born in his house, that they had congratulated him for him, and that he had acknowledged him. Shurayh said: "Keep your son." ‘Amir said: "For ‘Umar used to judge by that."