A black man used to clean the mosque, then he died and was buried at night. The Prophet ﷺ was informed of his death, and he said, "Take me to his grave."So they went to his grave, and he said, "These graves are filled with darkness for their occupants, but Allah illuminates them through my prayer over them."He came to the grave and prayed over him. Then a man from the Ansar said, "Messenger of Allah, my brother died and you did not pray over him."He asked, "Where is his grave?"The man told him, and the Messenger of Allah ﷺ went off with the Ansari.
أن أسود كان ينظف المسجد فمات، فدفن ليلا، وأتي النبي ﷺ، فأخبر، فقال: انطلقوا إلى قبره، فانطلقوا إلى قبره، فقال: إن هذه القبور ممتلئة على أهلها ظلمة، وإن الله ينورها بصلاتي عليها، فأتى القبر فصلى عليه، وقال رجل من الأنصار: يا رسول الله، إن أخي مات ولم تصل عليه. قال: فأين قبره؟ فأخبره فانطلق رسول الله ﷺ مع الأنصاري.
Ahmad (12517) narrated it from Sulayman bin Dawud Tayalisi, who said, Abu Amir, meaning al-Khazzaz, narrated to us from Thabit, from Anas, and he related it.Its chain is hasan because of Abu Amir, who is Salih bin Rustum Muzani, their freedman from Basra, about whom there is disagreement. Ibn Main declared him daif, while Abu Dawud considered him reliable. Ahmad said, "His hadith is sound." Ibn Adi said, "His hadith is scarce," and said, "Yahya Qattan narrated from him despite his rigorous scrutiny, and in my view there is no harm in him, and I have not seen from him any hadith that is very objectionable."