If anyone sees his brother committing a sin not leading to death, he should ask God, who will give life to those who commit this kind of sin. There is a sin that leads to death; I am not saying he should ask regarding that sin.
Believers should pray for a brother committing sin not leading to death, though John distinguishes a sin leading to death.
This verse applies intercessory prayer to the serious problem of sin within the community.
13I have written these things to you who believe in the name of the Son of God, so that you may know that you have eternal life. 14And this is the confidence that we have before Him: If we ask anything according to His will, He hears us. 15And if we know that He hears us in whatever we ask, we know that we already possess what we have asked of Him. 16If anyone sees his brother committing a sin not leading to death, he should ask God, who will give life to those who commit this kind of sin. There is a sin that leads to death; I am not saying he should ask regarding that sin. 17All unrighteousness is sin, yet there is sin that does not lead to death.