For most contemporary Christians the words “faith” and “belief” are interchangeable. The confusion, at least among Lutherans, came after Martin Luther’s death in 1546. His motto, “justified by grace through faith,” evolved into agreement to certain doctrinal articles which defined correct belief.
The root meaning of faith in Paul’s letters is “trust.” The demons in the upcoming gospel lesson from Luke 8: 26-39 know who Jesus is, but they don’t trust in him. “What have you to do with me, Jesus, Son of the Most High God?”
Faith is not something we achieve, an act of “believing the unbelievable,” or a “work” on our part. Faith is “revealed” to us as God’s work. For Paul, faith refers to the “faith of Jesus Christ” to the father as witnessed by his death on the cross and to Jesus’ mission to set humanity free from the bondage of sin. Faith is the grateful reception of God’s unmerited and undeserved gift of Christ to us.
Christians have faith in a person, not in a doctrine. We trust Jesus Christ for putting us in a right relationship with God, our Father. Faith is equivalent to trust in Jesus Christ and not an activity of the brain reflecting upon the meaning of that event, which is “belief.”
The demons possessing the man on the eastern shore of the sea of Galilee would have agreed that Luther’s Small Catechism was certainly correct in everything it said, but they would see it only as pointing to their destruction. They would have believed that Jesus was the Christ, the Son of God, but they would not have trusted him as the one commanded to save us (Ps. 71:3) nor as the One sent forth by God to redeem us from sin and the curse of the Law and thus adopt us as His children. (Gal. 4:4)