Al-Matalib al-'Aliyah 2993 — Prohibition of sitting with the Khawarij

It is narrated from Sayyiduna Jabir (may Allah be pleased with him) that a man passed by the Messenger of Allah (peace and blessings be upon him), and the people spoke about him and praised him highly (on account of his outward asceticism and piety). At that the Messenger of Allah (peace and blessings be upon him) asked: "Who will kill him?" Sayyiduna Abu Bakr (may Allah be pleased with him) said: "I will." So he set off and found him praying, having drawn a line around himself (for worship). Seeing him in that (devout) state, Sayyiduna Abu Bakr (may Allah be pleased with him) returned (out of hesitation) and did not kill him. Then the Messenger of Allah (peace and blessings be upon him) asked again: "Who will kill him?" Sayyiduna Umar (may Allah be pleased with him) said: "I will." He went and found him praying within that same line of his, so he too returned without killing him. Then the Messenger of Allah (peace and blessings be upon him) asked (a third time): "Who will kill him?" Sayyiduna Ali (may Allah be pleased with him) said: "I will." He (peace and blessings be upon him) said: "You (are the one suited to kill him), but I do not think you will find him." The narrator said: When Sayyiduna Ali (may Allah be pleased with him) got there, he saw that the man had already gone from there.
Abu Ya'la narrated it by way of Abu Khaythamah from Yazid bin Harun with this same previous chain.