Richard B. Gaffin writes:
What is the church? What is the purpose of the church? What does it mean for me to belong to the church? These are perennial questions, and each generation of Christians needs to be ready with informed answers. That readiness is so essential not only because such answers are basic to our identity as believers in Jesus Christ, but also because in every generation wrong answers crop up—answers that in varying ways mislead the church and blur its identity.
A key New Testament passage about the church is 1 Peter 2:4–5. One way we may usefully reflect on its teaching is to note, in contrast, what the church is not. This passage, we may say, shows us that the church is not made of rolling stones (believers are not rolling stones!). That’s true in two senses.