Muwatta Malik 1065
موطأ مالك#1065Sahihوَحَدَّثَنِي مَالِكٌ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنِ ابْنِ وَعْلَةَ الْمِصْرِيِّ، عَنْ عَبْدِ اللَّهِ بْنِ عَبَّاسٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِذَا دُبِغَ الإِهَابُ فَقَدْ طَهُرَ " .
Malik related to me from Zayd ibn Aslam from Ibn Wala al-Misri from Abdullah ibn Abbas that the Messenger of Allah, may Allah bless him and grant him peace, said, "A skin when it is tanned 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:
Salim al-HilaliSahih
In-book reference: 25:14