Narrated AbuHurayrah:

The Prophet (s.a.w.a.) said: If any one of you greets me, Allah returns my soul to me and I respond to the greeting.

Narrated Abu Hurairah:

The Messenger of Allah (s.a.w.a.) visited his mother's grave and wept and cause those around him to weep. The Messenger of Allah (s.a.w.a.) then said: I asked my Lord's permission to pray for forgiveness for her, but I was not allowed. I then asked His permission to visit her grave, and I was allowed. So visit graves, for they make one mindful of death.