The Muslims fighting Banu al-Asfar (the Romans)

Kathir bin Abdullah narrates from his father, who narrates from his grandfather (may Allah be pleased with him), that he said: I heard the Messenger of Allah (peace and blessings be upon him) say: "The world will not come to an end. O Ali bin Abi Talib!" Ali (may Allah be pleased with him) said: Here I am, O Messenger of Allah! He (peace and blessings be upon him) said: "Know that you will soon fight Banu al-Asfar (the Romans), and after you the believers will fight them too. The best of the believers, the people of the Hijaz, will go out against them; they will strive in the way of Allah, and they will not fear the blame of any blamer concerning Allah, until Allah, the Mighty and Majestic, conquers Constantinople and Rome at their hands through glorification (tasbih) and the declaration of Allah's greatness (takbir). Its fortifications will be demolished, and they will obtain such immense wealth there as they had never obtained before, so much so that they will divide the wealth by the (heaped) shield. Then a crier will cry out: O people of Islam! The Messiah, the Dajjal, has come out in your lands and among your children. So the people will scatter away from the wealth; some of them will take and some will leave it, and the one who takes will regret it and the one who leaves will regret it. They will say: Who is this crier? But they will not find out. They will say: Send a vanguard to Ludd; if the Messiah has come out, they will bring you news of him. They will go there and look, but will see nothing, and they will find the people at peace. So they will say: The crier did not cry out except for some great news, so make a firm resolve and then proceed on the right course. So they will resolve: Let us all go out together to Ludd; if the Messiah, the Dajjal, is there, we will fight him until Allah judges between us and him, and He is the best of judges; and if it is otherwise, then they are your lands, your clans and your armies, to which you will return."

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Woe to the Arabs from an evil that has drawn near! At the turn of (the year) sixty (AH), the trust will be regarded as booty, charity will be regarded as a penalty, testimony will be given on the basis of acquaintance, and judgement will be passed according to desires."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it with these additions.