Sunan Ibn Majah, Volume 4, Book 24, Hadith 2818 (DarusSalam) ⓘ
It was narrated from Ibn ‘Abbas that the flag of the Messenger of Allah was black, and his standard was white.
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ إِسْحَاقَ الْوَاسِطِيُّ النَّاقِدُ، حَدَّثَنَا يَحْيَى بْنُ إِسْحَاقَ، عَنْ يَزِيدَ بْنِ حَيَّانَ، سَمِعْتُ أَبَا مِجْلَزٍ، يُحَدِّثُ عَنِ ابْنِ عَبَّاسٍ، أَنَّ رَايَةَ، رَسُولِ اللَّهِ صلى الله عليه وسلم كَانَتْ سَوْدَاءَ وَلِوَاؤُهُ أَبْيَضُ .
also referenced under: Hadith 2818 (Reference) & Book 24, Hadith 2925 (In-Book)