عَنْ يُونُسَ بْنِ عُبَيْدٍ مَوْلَى مُحَمَّدِ بْنِ الْقَاسِمِ قَالَ بَعَثَنِي مُحَمَّدُ بْنُ الْقَاسِمِ إِلَى الْبَرَاءِ بْنِ عَازِبٍ رَضِيَ اللَّهُ عَنْهُ أَسْأَلُهُ عَنْ رَايَةِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ مَا كَانَتْ قَالَ كَانَتْ سَوْدَاءَ مُرَبَّعَةً مِنْ نَمِرَةٍ
Yunus bin Ubaid says: Muhammad bin Qasim sent me to Sayyiduna Bara’ bin Azib (may Allah be pleased with him), so that I could ask him about the flag of the Messenger of Allah (peace and blessings be upon him), what it was like. He said: It was square in shape and striped black in color.