And the prayer of faith will save the sick, and the Lord will raise him up. James 5:15
The prayer of faith refers to the prayers of the people praying for the sick person. Not the faith of the sick person by itself. In this context, Elders of the Church. Will save carries two meanings here: The sick person will experience 1. Physical healing and more importantly 2. Spiritual Healing or salvation.
The healing here may be physical, but the sickness is connected to a moral infirmity: the remedy is clearly the confession of sins. Which is in the subsequent verse … V 16: Therefore confess your sins
The powerful and effective prayer of the righteous is, thus, connected to the confession of sins.
Throughout the Gospels, we see that Jesus healed both Spiritually & Physically. God is well able to heal us when we cry unto Him with a pure heart and in His Will. He is Jehovah Rapha.