It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) visited his mother's grave, and he (peace and blessings be upon him) wept and made those around him weep too. Then he said: "I asked my Lord for permission to visit her grave, and He gave me permission; and I asked permission to pray for forgiveness for her, but I was not given permission. So visit the graves, for they remind of death." This hadith is sahih (authentic) on the condition of Muslim, but they did not record it.