Sunan Abi Dawud 5160
سنن أبي داود#5160Sahihحَدَّثَنَا أَبُو كَامِلٍ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، عَنِ الأَعْمَشِ، بِإِسْنَادِهِ وَمَعْنَاهُ نَحْوَهُ قَالَ كُنْتُ أَضْرِبُ غُلاَمًا لِي أَسْوَدَ بِالسَّوْطِ وَلَمْ يَذْكُرْ أَمْرَ الْعِتْقِ .
The tradition mentioned above has also been transmitted by al-A’mash in a similar way to same way to the same effect through a different chain of narrators
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
In-book reference: 43:388