It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that there was a black woman or man who used to serve the Prophet's Mosque (by sweeping and keeping it clean). One day, the Holy Prophet (peace and blessings be upon him) did not see that person. The Holy Prophet (peace and blessings be upon him) asked the noble companions (may Allah be pleased with them) about him/her, and they informed him that he/she had passed away. The Holy Prophet (peace and blessings be upon him) said, "Why did you not inform me?" The noble companions (may Allah be pleased with them) submitted that it was night time (so they did not consider it appropriate to trouble him). The Holy Prophet (peace and blessings be upon him) said, "Show me his/her grave." The noble companions (may Allah be pleased with them) showed it to him, so the Holy Prophet (peace and blessings be upon him) went to the grave and prayed for his/her forgiveness.