Jas 5:16-18
"Therefore, confess your sins to one another and pray for one another, that you may be healed. The prayer of a righteous person has great power as it is working. Elijah was a man with a nature like ours, and he prayed fervently that it might not rain, and for three years and six months it did not rain on the earth."
The effective prayer (energoumene — that operates, that acts) of the righteous has great power. Elijah as an example: a man of 'similar passions' (homoiopathes) — not a superhero, but an ordinary man. Faithful prayer can change the weather — how much more can it change hearts.
Jas 5:19-20
"My brothers, if anyone among you wanders from the truth and someone brings him back, let him know that whoever brings back a sinner from his wandering will save his soul from death and will cover a multitude of sins."
The ministry of restoration: bringing back the one who has strayed is saving a soul from death. The Church is responsible for those who stray — not only for those inside. The covering of sins (kalypsei plethos hamartion) is the result of restoration.