Sunan Abi Dawud 4123
سنن أبي داود#4123Sahihحَدَّثَنَا مُحَمَّدُ بْنُ كَثِيرٍ، أَخْبَرَنَا سُفْيَانُ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ وَعْلَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " إِذَا دُبِغَ الإِهَابُ فَقَدْ طَهُرَ " .
Narrated Ibn 'Abbas:That he heard the Messenger of Allah (ﷺ) say: When a skin is tanned, it is pure
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
Zubair Ali ZaiSahih Muslim (366)
In-book reference: 34:104