Someone said to Amr bin As, "The Hour will come when the Romans are the most numerous of people."Amr bin As replied, "Be careful what you say."The man answered, "I am telling you what I heard from the Messenger of Allah ﷺ."Amr bin As then said, "If you have indeed said that, then they possess four qualities. They are the quickest of people to recover after a setback, the best of people to the poor, the destitute, and the weak, the most forbearing of people during times of trial, and the fourth is a fine and beautiful trait, they are the most resistant of people to the oppression of kings."
حدثنا علي بن عياش حدثنا ليث بن سعد حدثنا موسى بن علي عن أبيه
لعمرو بن العاص تقوم الساعة والروم أكثر الناس فقال له عمرو بن العاص أبصر ما تقول قال أقول لك ما سمعت من رسول الله ﷺ فقال عمرو بن العاص إن تكن قلت ذاك إن فيهم لخصالا أربعا إنهم لأسرع الناس كرة بعد فرة وإنهم لخير الناس لمسكين وفقير وضعيف وإنهم لأحلم الناس عند فتنة والرابعة حسنة جميلة وإنهم لأمنع الناس من ظلم الملوك
Its isnad is sahih. Musa bin Ali bin Rabah bin Qusayr is reliable, as is his father, and they have both already been mentioned.Muslim narrated the hadith (4/2222, no. 2898), in the Book of Tribulations, "The Hour will come while the Byzantines are the most numerous of people." This hadith is not praise for the Byzantines, but rather a form of awareness of the enemy's characteristics, and a warning concerning that.