Musannaf Ibn Abi Shaybah 40346 — Reports on the tribulation

It is narrated from Sayyiduna Umar (may Allah be pleased with him) that he said: We were sitting with the Prophet (peace and blessings be upon him) when a man with intensely white clothes and intensely black hair came to him. No trace of travel could be seen on him, and none of us knew him. He drew near to him (peace and blessings be upon him) until he brought his knees close to his knees, placed his palms on his thighs and said: "O Muhammad (peace and blessings be upon him)! When will the Hour be established?" He (peace and blessings be upon him) said: "The one being asked about it does not know more than the one asking. But among its signs are that a slave woman will give birth to her master, and that the barefoot and naked people who herd goats will vie with one another in buildings."