“ . . the prayer of faith will heal the sick and the Lord will raise them up. If they have sinned, they will be forgiven.” James 5:15
Who is a “righteous” person? A righteous person is one who has Jesus’s righteousness in him because he has surrendered his whole self to Jesus. Not my righteousness but Jesus’ righteousness is the only thing that is going to save me, the only thing that is going to make me holy, as God is holy. So if you want to have prayer that is powerful and effective, what do you have to do? You have to surrender; not just once, but every single day, every hour, every minute. Most of the time we’re too busy to even consider that. But if you try it, and you keep on trying, eventually it gets to be a habit; you enter a zone where you’re in constant contact with the Spirit that is in you, and you begin to “rejoice evermore, pray without ceasing, and give thanks in all things,” because that really is “the will of God in Christ Jesus for you” (1 Thessalonians 5:16-18). That’s where “righteous” comes from, and that’s what it takes to be a servant in the Biblical sense—it’s all about God, “Christ in you, the hope of glory.” (Colossians 1:27).
The righteous person is not some preacher, prophet, priest, or king, but rather you and every person who has the Spirit of God residing in his or her heart. So if you pray over them and anoint them with oil, they will be delivered, healed, and made whole, because you are one of those special people whom God has anointed to do His will, to fulfill His purposes on this earth.
The part about “the prayer of faith” is a prayer that is spoken by a person who has God’s Spirit living in her; it’s not something she has to “work up”; it’s something that is already happening in her heart, soul, and spirit because of the presence of God’s Spirit in her. It’s one of those “rivers of living water” that flows out of her because she trusts Jesus as a condition of her very being; it’s not just a momentary act of her will.