It is narrated from Hazrat Anas (may Allah be pleased with him) that there was an Abyssinian who used to clean the mosque. One day he passed away, and the people buried him during the night. When the Prophet (peace and blessings be upon him) found out, he said to the companions (may Allah be pleased with them), "Let us go to his grave." So they went to his grave. The Prophet (peace and blessings be upon him) said, "There is darkness upon the dwellers of these graves. By the blessing of my prayer, Allah will illuminate them." Thus, the Prophet (peace and blessings be upon him) offered the funeral prayer at his grave. Upon this, an Ansari said, "O Messenger of Allah (peace and blessings be upon him)! My brother had passed away, but you did not offer the funeral prayer at his grave." The Prophet (peace and blessings be upon him) asked, "Where is his grave?" The Ansari pointed it out, so the Prophet (peace and blessings be upon him) went with him as well.