Sahih Muslim Book - 11, Hadith - 2259

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِى شَيْبَةَ وَزُهَيْرُ بْنُ حَرْبٍ قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ عُبَيْدٍ عَنْ يَزِيدَ بْنِ كَيْسَانَ عَنْ أَبِى حَازِمٍ عَنْ أَبِى هُرَيْرَةَ قَالَ زَارَ النَّبِىُّ -صلى الله عليه وسلم- قَبْرَ أُمِّهِ فَبَكَى وَأَبْكَى مَنْ حَوْلَهُ فَقَالَ « اسْتَأْذَنْتُ رَبِّى فِى أَنْ أَسْتَغْفِرَ لَهَا فَلَمْ يُؤْذَنْ لِى وَاسْتَأْذَنْتُهُ فِى أَنْ أَزُورَ قَبْرَهَا فَأُذِنَ لِى فَزُورُوا الْقُبُورَ فَإِنَّهَا تُذَكِّرُ الْمَوْتَ ».

It was narrated that Abu Hurairah said: "The Prophet (s.a.w) visited the grave of his mother, and he wept and caused those around him to weep too. Then he (s.a.w) said: 'I asked my Lord for permission to pray for forgiveness for her, but He did not grant me permission. And I asked Him for permission to visit her grave and He gave me permission, so visit graves, for they will remind you of death."'