Sahih Muslim: Hadith 7202

Once there blew a red storm in Kufah that there came a person who had nothing to say but (these words): `Abdullah b. Mas`ud, the Last Hour has come. He (`Abdullah b. Mas`ud) was sitting reclining against something, and he said: The Last Hour would not come until shares of inheritance are not distributed and there is no rejoicing over spoils of war. Then he said pointing towards Syria, with the gesture of his hand like this: The enemy shall muster strength against Muslims and the Muslims will muster strength against them (Syrians). I said: You mean Rome? And he said: Yes, and there would be a terrible fight and the Muslims would prepare a detachment (for fighting unto death) which would not return but victorious. They will fight until night will intervene them; both the sides will return without being victorious and both will be wiped out. The Muslims will again prepare a detachment for fighting unto death so that they may not return but victorious. When it would be the fourth day, a new detachment out of the remnant of the Muslims would be prepared and Allah will decree that the enemy should be routed. And they would fight such a fight the like of which would not be seen, so much so that even if a bird were to pass their flanks, it would fall down dead before reaching the end of them. (There would be such a large scale massacre) that when counting would be done, (only) one out of a hundred men related to one another would be found alive. So what can be the joy at the spoils of such war and what inheritance would be divided! They would be in this very state that they would hear of a calamity more horrible than this. And a cry would reach them: The Dajjal has taken your place among your offspring. They will, therefore, throw away what would be in their hands and go forward sending ten horsemen, as a scouting party. Allah's Messenger (ﷺ) said: I know their names and the names of their forefathers and the color of their horses. They will be the best horsemen on the surface of the earth on that day or amongst the best horsemen on the surface of the earth on that day.