Sunan Abu Dawud
3941
Sahih+3

The tradition mentioned above has also been transmitted by Ibn 'Umar to the same effect through a different chain of narrators. Nafi' sometimes said:He will be emancipated to the extent of the share which he emancipated, and sometimes he did not say these words

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid