Sunan Abi Dawud 2591
سنن أبي داود#2591SahihNarrated Al-Bara' ibn Azib: Yunus ibn Ubayd, client of Muhammad ibn al-Qasim, said that Muhammad ibn al-Qasim sent to al-Bara' ibn Azib to ask him about the standard of the Messenger of Allah (ﷺ). He said: It was black and square, being made of a woollen rug
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautHasan Lighairihi
Zubair Ali ZaiIsnaad Hasan
In-book reference: 15:115