Al-Matalib al-'Aliyah 2994-1 — Prohibition of sitting

It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that a man was mentioned before the Messenger of Allah (peace and blessings be upon him) who struck the enemy hard and was very devoted to worship. He (peace and blessings be upon him) said: "I do not recognise this man." The Companions said: Of course (O Messenger of Allah)! His qualities and appearance are such and such. He (peace and blessings be upon him) again said: "I do not know him." Meanwhile that man appeared, and the Companions said: O Messenger of Allah! This is the man. The Messenger of Allah (peace and blessings be upon him) said: "I did not recognise him. This is the first (trouble-making) faction that I see in my Ummah; on his face is the mark of the ill omen of Satan." Then, when the man came near, he gave the greeting of peace and the Companions returned his greeting. Then he (peace and blessings be upon him) asked him: "I ask you by Allah: when you came to us, was it not in your heart that there is no one in this whole gathering better than you?" He replied: 'Allahumma na'am' (O Allah, yes). Then the man entered the mosque and began to pray. The Messenger of Allah (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) entered the mosque and found him standing in prayer. He thought to himself: Prayer certainly has a sanctity and a right; (it is better that) I take the command of the Messenger of Allah (peace and blessings be upon him) about it again. So he came back, and the Prophet (peace and blessings be upon him) asked him: "Did you kill him?" He said: No; I saw him standing in prayer, and I felt that prayer has a sanctity and a right. If that is still your command, I will kill him. He (peace and blessings be upon him) said: "You are not the one to kill him." Then he said: "O Umar! Go and kill him." So Sayyiduna Umar (may Allah be pleased with him) entered the mosque and found him in prostration. He waited a long while, then Sayyiduna Umar (may Allah be pleased with him) thought to himself: Prostration certainly has a right; if only I consult the Messenger of Allah (peace and blessings be upon him) again, for one better than me (Abu Bakr) also did the same. So he came to the Prophet (peace and blessings be upon him), who asked: "Did you kill him?" He said: No; I found him in prostration, and I felt that prostration has a great right. If you still wish me to kill him, I will do so? He (peace and blessings be upon him) said: "You too are not the one to kill him. O Ali! Get up; if you find him, you are the one to kill him." When Sayyiduna Ali (may Allah be pleased with him) got there, he saw that the man had already left the mosque. He returned to the Messenger of Allah (peace and blessings be upon him), who asked: "Did you kill him?" He said: No. The Messenger of Allah (peace and blessings be upon him) said: "Had he been killed today, no two men of my Ummah would ever have differed or split until the coming of the Dajjal."
This hadith is gharib (singular), and the narrator in its chain, Abu Ma'shar, is da'if (weak).