As-salamu alaikum wa Rahmatullahi wa Barakatoh,
Imām Alī ibn Mūsā al-Rezā (alayhi salām) said:
"One who does not have any means to get his sins forgiven then he should recite Salwaat on Mohammad (salla llāhu ʿalayhi wa-alehe wa-sallam) and his progeny abundantly as it wipes out the sins.
" Then he (alayhi salām) said: Reciting Salwaat on Mohammad (salla llāhu ʿalayhi wa-alehe wa-sallam) and his progeny is like
Tasbeeh سُبْحَانَ اللَّهِ (reciting Subhanallah),
Tahleel لَا إِلٰهَ إِلَّا الَّلهِ (reciting La Ilaha Illallah)
and Takbir اَللَّهُ اَكْبَرُ (reciting Allahu Akbar) near Allah, the High."
[References : Beharul Anwaar, vol 94, chapter 29, hadees# 3, pg. 47-48, narrating from Oyoon-e-Akhbaar-e-Reza]