"13Is any one of you in trouble? He should pray. Is anyone happy? Let him sing songs of praise. 14Is any one of you sick? He should call the elders of the church to pray over him and anoint him with oil in the name of the Lord. 15And the prayer offered in faith will make the sick person well; the Lord will raise him up. If he has sinned, he will be forgiven. 16Therefore confess your sins to each other and pray for each other so that you may be healed. The prayer of a righteous man is powerful and effective.
17Elijah was a man just like us. He prayed earnestly that it would not rain, and it did not rain on the land for three and a half years. 18Again he prayed, and the heavens gave rain, and the earth produced its crops.
19My brothers, if one of you should wander from the truth and someone should bring him back, 20remember this: Whoever turns a sinner from the error of his way will save him from death and cover over a multitude of sins.
We live in a world that refuses to define or believe in an absolute Truth. Verse 19 shows us that there is truth in this world and that the effect of turning away from truth is SIN. If truth is relative then there can be no sin, but we know that sin exists.
Why do we have to define when a baby becomes a baby, why do have to fight child abuse, why do we choose to disobey traffic laws, why do we slack off at work, why do we pirate music and movies? Its because sin and a skewed moral compass due to lack of truth.
James is calling us to not live for this world, and to actively stand out against the sins of this world. Live for Gods world. Verse 20 bring back those who are in sin.
Dont be so caught up in your own sin that you cant be concerned for the salvation of a brother. Care about restoring and redeeming those struggling with the truth.