Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates: There was a person who used to clean the mosque; he passed away. Once, the Prophet Muhammad (peace be upon him) did not find him present and inquired about him: The Prophet (peace be upon him) asked, "What happened to so-and-so?" The people informed him, "He has passed away." The Prophet (peace be upon him) said, "Why did you not inform me?" The people had considered his matter insignificant. The Prophet (peace be upon him) said to his companions, "You people come and guide me to his grave." Then the Prophet (peace be upon him) went and offered the funeral prayer for that person. Then the Prophet (peace be upon him) said: "These graves are dark for their inhabitants, so because of my offering the funeral prayer for them, Allah Almighty illuminates them for them."