Not graded
Hisn al-Muslim (Fortress of the Muslim) 219
قَالَ النَّبِيُّ صلى الله عليه وسلم: ((مَنْ صَلَّى عَلَيَّ صَلاَةً صَلَّى اللَّهُ عَلَيْهِ بِهَا عَشْراً)).
(The Prophet (PBUH) said: ‘Whoever sends a prayer upon me, Allah sends ten upon him.)
Cited in Hisn al-Muslim (Fortress of the Muslim) (No. 219).