Musnad Abu Ya'la al-Mawsili 149:63

Ishaq narrated to us, Sufyan narrated to us, from al-Zuhri, from Urwah, from Aisha, who said: Sa’d and Abd ibn Zam’ah disputed before the Messenger of Allah (peace be upon him). Sa’d said: "My brother entrusted me that if I arrived in Mecca, I should take the son of the slave-woman of Zam’ah, for he is my son." Abd ibn Zam’ah said: "O Messenger of Allah, he is my brother and the son of my father’s slave-woman, born on my father’s bed." He (the Prophet) saw a clear resemblance to Utbah. He said: "He is for you. The child is for the bed, and veil yourself from him, O Sawdah."