Sunan an Nasai
The Book of al-Fara' and al-'Atirah
Hadith #20
41.20
أَخْبَرَنَا قُتَيْبَةُ، وَعَلِيُّ بْنُ حُجْرٍ، عَنْ سُفْيَانَ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنِ ابْنِ وَعْلَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَيُّمَا إِهَابٍ دُبِغَ فَقَدْ طَهُرَ " .
It was narrated that Ibn 'Abbas said:"The Messenger of Allah said: 'Any skin that is tanned has been purified