Muwatta Malik 1498

وَحَدَّثَنِي مَالِكٌ، عَنْ يَحْيَى بْنِ سَعِيدٍ، أَنَّ سَعِيدَ بْنَ الْمُسَيَّبِ، كَانَ يَقُولُ إِذَا دَبَّرَ الرَّجُلُ جَارِيَتَهُ فَإِنَّ لَهُ أَنْ يَطَأَهَا وَلَيْسَ لَهُ أَنْ يَبِيعَهَا وَلاَ يَهَبَهَا وَوَلَدُهَا بِمَنْزِلَتِهَا ‏.‏

Malik related to me from Yahya ibn Said that Said ibn al-Musayyab used to say, "When a man makes his slave-girl mudabbara, he can have intercourse with her. He cannot sell her or give her away and her children are in the same position as her

Reference

Muwatta Malik 1498

In-book

Book 40, Hadith 2