My father narrated to us. He said: Sa`d b. `Abdullah narrated to us from Ahmad b. Muhammad b. `Isa from `Ali b. al-Hakam from Muthanna al-Hannat from Abi Basir from al-Sadiq Ja`far b. Muhammad . He said: I heard him say:

Whoever prays four units with two hundred recitations of qul huwallahu ahad – fifty times per unit – there will not remain a sin between him and Allah except that it has been forgiven for him.