مُوَطَّأُ مَالِكٍ
Muwatta Malik 1500
The Mudabbar
حَدَّثَنِي مَالِكٌ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، دَبَّرَ جَارِيَتَيْنِ لَهُ فَكَانَ يَطَؤُهُمَا وَهُمَا مُدَبَّرَتَانِ .
Malik related to me from Nafi that Abdullah ibn Umar made two of his slave-girls mudabbara, and he had intercourse with them while they were mudabbara.
Arabic/English book reference: Book 40, Hadith 4