Islam

It was narrated on the authority of Umar (may Allah be pleased with him), who said:

While we were one day sitting with the Messenger of Allah (peace be upon him), there appeared before us a man dressed in extremely white clothes and with very black hair. No traces of journeying were visible on him, and none of us knew him. He sat down close by the Prophet (peace be upon him), rested his knee against his thighs, and said, “O Muhammad! Inform me about Islam.”