Sunan Ibn Majah, Book 24, Hadith 2913 (In-Book) ⓘ
It was narrated from Sa’ib bin Yazid, if Allah wills, that the Prophet wore two coats of mail on the Day of Uhud, one over the other.
حَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ، حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ يَزِيدَ بْنِ خُصَيْفَةَ، عَنِ السَّائِبِ بْنِ يَزِيدَ، إِنْ شَاءَ اللَّهُ تَعَالَى . أَنَّ النَّبِيَّ صلى الله عليه وسلم يَوْمَ أُحُدٍ أَخَذَ دِرْعَيْنِ كَأَنَّهُ ظَاهَرَ بَيْنَهُمَا .
also referenced under: Hadith 2806 (Reference) & Volume 4, Book 24, Hadith 2806 (DarusSalam)