It is narrated from Hazrat Abu Hurairah (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 Prophet (peace and blessings be upon him) did not see that person. The Prophet (peace and blessings be upon him) asked the companions (may Allah be pleased with them) about him/her, and they informed him that he/she had passed away. The Prophet (peace and blessings be upon him) said: "Why did you not inform me?" The companions (may Allah be pleased with them) replied that he/she was an ordinary person (so they did not consider it appropriate to trouble the Prophet). The Prophet (peace and blessings be upon him) said: "Show me his/her grave." The companions (may Allah be pleased with them) showed him, so the Prophet (peace and blessings be upon him) went to the grave and prayed for his/her forgiveness.