Musannaf Ibn Abi Shayba 20:42

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Sufyan, from Dawud ibn Abi Hind, from ‘Abdullah ibn ‘Ubayd ibn ‘Umayr, who said: A brother from Banu Zurayq wrote to me asking about whom the Messenger of Allah (may Allah bless him and grant him peace) assigned the son of the woman involved in *li’an* (mutual cursing). So I wrote back to him that the Messenger of Allah (may Allah bless him and grant him peace) assigned him to his mother; she is in the position of his father and in the position of his mother.