Narrated 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.
Hadith Referenceسنن ابي داود / كتاب الجهاد / 2591
Hadith Gradingالألبانی:صحيح دون قوله مربعة | زبیر علی زئی:إسناده حسن, مشكوة المصابيح (3888)
Hadith Takhrij« سنن الترمذی/الجھاد 10 (1680)، (تحفة الأشراف: 1922)، وقد أخرجہ: مسند احمد (4/297) (صحیح) » (لیکن «مربعة» - چوکور - کا لفظ صحیح نہیں ہے اس لیے کہ ابو یعقوب اسحاق بن ابراہیم ثقفی کوفی میں ضعف ہے ان کی توثیق ابن حبان نے کی ہے ، اور اس لفظ کی روایت میں ان کا کوئی شاہد یا متابع نہیں ہے )
Benefits and Issues: ➊ (Al-Liwa’) refers to the greatest banner, and (Ar-Rayah) refers to its subsidiary flags. And for the Noble Prophet (sallallahu alayhi wa sallam), there will be the (Liwa’ al-Hamd) on the Day of Resurrection.
➋ Shaykh al-Albani says: This narration is authentic; however, the word (murabba‘a) meaning “square-shaped” is not authentic.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 2591
Explanation: 1: It is established from some narrations that "La ilaha illallah Muhammadur Rasulullah" was written on the banner of the Prophet sallallahu alayhi wa sallam.
Note: (However, the word "square" is not authentic; its narrator Abu Ya'qub al-Thaqafi is weak, and there is neither a corroborator nor a witness for this wording.)
Source: Sunan al-Tirmidhi – Majlis ‘Ilmi Dar al-Da‘wah, New Delhi Edition, Page: 1680