NET

16 So confess your sins to one another and pray for one another so that you may be healed. The prayer of a righteous person has great effectiveness.

Darby

16 Confess therefore your^D9217 offences to one another, and pray for one another, that ye may be healed. [The] fervent^D9218 supplication of the righteous [man] has much power.

Darby Bible Notes

your - Lit. 'the.' fervent - Or, 'operative,' 'working effectually,' if the word be taken as a participle, as elsewhere in the New Testament. The A.V. combines the two ideas, 'the effectual fervent prayer,' but it is hardly both. I do not think it is inwrought by spiritual power. It is the person who is 'fervent.'

KJV

16 Confess [your] faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much.