Not graded
Hisn al-Muslim (Fortress of the Muslim) 220
وَقَالَ صلى الله عليه وسلم: ((لاَ تَجْعَلُوا قَبْرِي عِيداً وَصَلُّوا عَلَيَّ؛ فَإِنَّ صَلاَتَكُم تَبْلُغُنِي حَيْثُ كُنْتُمْ)).
(He (PBUH) also said: ‘Do not take my grave as a place of habitual ceremony. Send prayers upon me, for verily your prayers reach me wherever you are.)
Cited in Hisn al-Muslim (Fortress of the Muslim) (No. 220).