Musannaf Ibn Abi Shayba 13:2866

Abu Bakr narrated to us, he said: Waki' narrated to us, he said: Isra'il narrated to us, from Jabir, from 'Amir, 'Ata', and Muhammad ibn 'Ali, they said: There is no harm in separating the *muwalladat* (slave women born in the land of Islam).