Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates: A man was mentioned before the Prophet (peace and blessings be upon him) who inflicted heavy losses on the enemy and was very diligent in worship and devotion. The Prophet (peace and blessings be upon him) said: I do not recognise him. The narrator said: His description is such-and-such. The Prophet (peace and blessings be upon him) said: I do not recognise him. The narrator says: Meanwhile that man appeared, and the narrator said: This is that man. The Prophet (peace and blessings be upon him) said: I did not recognise him. This is the first horn that I see in my Ummah, and there is a mark of Satan in him. When the man came near, he greeted with salam, and the Prophet (peace and blessings be upon him) returned his greeting. The Prophet (peace and blessings be upon him) asked him: When you came before us, did you think to yourself that among all these people there is no one more excellent than you? He replied: By Allah, yes! Then that man entered the mosque and began to pray. The Prophet (peace and blessings be upon him) said to Sayyiduna Abu Bakr (may Allah be pleased with him): Get up and kill him. Sayyiduna Abu Bakr (may Allah be pleased with him) went in and found the man standing in prayer. Sayyiduna Abu Bakr (may Allah be pleased with him) thought to himself: Prayer has a particular sanctity and right; it would be appropriate if I asked the Prophet (peace and blessings be upon him) about this again. He came to the Prophet (peace and blessings be upon him), and the Prophet (peace and blessings be upon him) asked him: Have you killed him? He said: No! I found him praying, and I thought that prayer has sanctity and a particular right. If you wish me to kill him, I will kill him. The Prophet (peace and blessings be upon him) said: You are not the one for him. O Umar! You go and kill him. Sayyiduna Umar (may Allah be pleased with him) entered the mosque, and the man was in prostration. Sayyiduna Umar (may Allah be pleased with him) waited for him for quite a long time; then Sayyiduna Umar (may Allah be pleased with him) thought to himself: Prostration has a particular right; it would be appropriate if I asked the Prophet (peace and blessings be upon him) about this again, for one who is better than me asked the Prophet (peace and blessings be upon him) again. Then he came to the Prophet (peace and blessings be upon him), and the Prophet (peace and blessings be upon him) asked: Have you killed him? He said: No! I saw him in prostration, and I thought that prostration has a particular right; but if you wish me to kill him, I will kill him. The Prophet (peace and blessings be upon him) said: You are not the one for him. O Ali! You are the one for him, if you find him. Sayyiduna Ali (may Allah be pleased with him) went in and found that the man had already left the mosque. He came back to the Prophet (peace and blessings be upon him), and the Prophet (peace and blessings be upon him) asked: Have you killed him? He said: No! The Prophet (peace and blessings be upon him) said: If this man had been killed, not even two men of my Ummah would have differed until the Dajjal emerges. Then the Prophet (peace and blessings be upon him) told them about the nations and said: "The Ummah of Sayyiduna Musa (peace be upon him) split into seventy-one groups, of which seventy will go to Hell and one will go to Paradise. The Ummah of Sayyiduna Isa (peace be upon him) split into seventy-two groups, of which seventy-one will go to Hell and one will go to Paradise. Then the Prophet (peace and blessings be upon him) said: My Ummah will exceed both these groups by one sect; seventy-two of them will go to Hell and one will go to Paradise." The people said: O Messenger of Allah! Who will they (that is, those who go to Paradise) be? The Prophet (peace and blessings be upon him) said: The Jama'ah. Ya'qub bin Zayd says: Whenever Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) narrated this hadith from the Prophet (peace and blessings be upon him), he would also recite this verse of the Qur'an with it: "And among the people of Musa is a group who guide by the truth and by it establish justice." Then, when he mentioned the Ummah of Sayyiduna Isa (peace be upon him), he recited this verse: "And if the People of the Book had believed (in the Prophet, peace and blessings be upon him) and been mindful of Allah, We would have removed from them their misdeeds and admitted them to Gardens of Bliss." Then, when he mentioned our Ummah, he recited this verse: "And among those We have created is a group who guide by the truth and by it establish justice (or judge)."
Abu Ya'la recorded it; its chain contains Abu Ma'shar Najih, in whom there is weakness. Various chains of this hadith have already passed in the chapter on fighting the Khawarij.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الفتن - أعاذنا الله منها / 12095