Sunan an-Nasa'i, hadith 2034

أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ عُبَيْدٍ، عَنْ يَزِيدَ بْنِ كَيْسَانَ، عَنْ أَبِي حَازِمٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ ‏:‏ زَارَ رَسُولُ اللَّهِ صلى الله عليه وسلم قَبْرَ أُمِّهِ فَبَكَى وَأَبْكَى مَنْ حَوْلَهُ وَقَالَ ‏:‏ ‏ "‏ اسْتَأْذَنْتُ رَبِّي عَزَّ وَجَلَّ فِي أَنْ أَسْتَغْفِرَ لَهَا فَلَمْ يُؤْذَنْ لِي، وَاسْتَأْذَنْتُ فِي أَنْ أَزُورَ قَبْرَهَا فَأَذِنَ لِي، فَزُورُوا الْقُبُورَ فَإِنَّهَا تُذَكِّرُكُمُ الْمَوْتَ ‏"‏ ‏.‏

It was narrated that Abu Hurairah said:"The Messenger of Allah visited the grave of his mother and wept, and caused those around him to weep. He said: 'I asked my Lord for permission to pray for forgiveness for her and He did not give me permission, and I asked Him for permission to visit her grave and He gave me permission, so visit the graves, for they will remind you of death