“The purpose of Scripture is not merely to give us an authoritative list of things we must believe but also to exhort us, command us, inspire our imaginations, put songs in our hearts, question us, sanctify us, and so on” (John Frame, The Doctrine of the Knowledge of God, 78).
The purpose of Scripture is twofold: things to be believed and things to be done (the application of Scripture). The purpose of Scripture propels Christians to take their confession of faith and see what they can do (accomplish) with it; that is, “this”, e.g., Thou shalt love thy neighbor!, goes “there”, e.g., the homeless man at the soup kitchen.
As Luke says, “The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach . . . (Acts 1:1). The Gospel of Luke was about what Jesus Christ began to do and teach, and the Book of Acts is about what Jesus Christ continued to do and teach through the Apostles and through the Church. This is the context for a Christian approach to understanding the purpose of Scripture: Scripture teaches us what Jesus Christ continues to do and teach through us.