How do we know the effectiveness of prayer according to the Bible?

The effectiveness of prayer is underscored in James 5:15, which states that the prayer of faith shall save the sick and raise them up. This illustrates that prayer is not merely a ritual but a profound spiritual act that invites God's intervention. While prayer can lead to physical healing, it also encompasses forgiveness of sins, affirming a holistic understanding of a person's well-being—physical, mental, and spiritual. Elders are to pray in faith, reflecting reliance on God's authority and assurance in His willingness to respond to the faithful.