Hisnul Muslim 220

Excellence of sending prayers upon the Prophet saws

وقال صلى الله عليه وسلم : " لا تجعلوا قبري عيداً وصلوا علي ؛ فإن صلاتكم تبلغني حيث كنتم "

The Prophet (SAW) said: Do not make my grave a place of ritual celebration, but pray for Allah's blessings upon me, for your blessings reach me from wherever you are.