Musannaf Ibn Abi Shayba 13:1767

Abu Bakr narrated to us, he said: Ali bin Mushir narrated to us, from Sa'id bin Abi 'Aruba, from Qatada, from an-Nadr bin Anas, from Bashir bin Nahik, from Abu Hurayra, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever emancipates a portion or a share that he owns in a slave, then he is responsible for completing his emancipation from his own wealth, if he has wealth. And if he does not have wealth, the slave is to work to earn his value, without being overburdened."