حَدَّثَنَا نَصْرُ بْنُ عَلِيٍّ، حَدَّثَنَا أَبُو أَحْمَدَ، حَدَّثَنَا سُفْيَانُ، عَنْ عُبَيْدِ اللَّهِ، عَنْ نَافِعٍ، أَنَّ ابْنَ عُمَرَ، كَانَ يُرْدِفُ مَوْلاَةً لَهُ يُقَالُ لَهَا صَفِيَّةُ تُسَافِرُ مَعَهُ إِلَى مَكَّةَ ‏.‏

Nafi` said : Ibn `Umr used to seat his slave girl called Safiyyah behind him(on the Camel) and thus she travelled to Makkah in his company. Translation Not Available

Book Ref: Sunan Abi Dawud Book 11 Hadith 1728
Web Ref:  Sunan Abi Dawud Book 10 Hadith 1724