حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا هِشَامٌ، عَنْ قَتَادَةَ، عَنِ الْحَسَنِ، قَالَ لاَ يُقَادُ الْحُرُّ بِالْعَبْدِ ‏.‏

It was narrated from Hisham, from Qatadah, from Al-Hasan, who said: "A free man should not be subjected to retaliation in return for a slave." Translation Not Available

Book Ref: Sunan Abi Dawud Book 41 Hadith 4518
Web Ref:  Sunan Abi Dawud Book 40 Hadith 4503