This is an OldTestament concept whereby good men can obtain salvation for evil men through prayer.

Such a concept circumvents the necessity to preach the Gospel to every creature. It is the preaching of the Word which produces the faith by which Grace comes to a person.

Grace only comes to a person who comes to Christ Jesus in faith of who He is and what He has done for them.

What is the purpose of prayer? It is to prepare us to be able to sow the seed of His Word with the unction of His HolySpirit.