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. Elias was a man subject to like passions as we are, and he prayed earnestly that it might not rain: and it rained not on the earth by the space of three years and six months. And he prayed again, and the heaven gave rain, and the earth brought forth her fruit. (James 5:16-18 KJV)
As the body of Christ, we need healing. Many physical illnesses stem from stress associated with strained relationships. When we make ourselves open to others and confess our faults so others can pray for us it has the effect of lifting a big burden from our shoulders. It brings a measure of healing to our souls as well as easing the strain of stress that tears at us physically.