In Romans 8:9 Paul introduces a concept similar to Peter’s assertion that believers are being built up as a spiritual house. Paul explains that the Spirit of Christ (the Holy Spirit) lives in every believer. Paul also illustrates the growth of believers together by describing them as a whole building that is being fitted together and growing into a holy temple in the Lord (Ephesians 2:21). These illustrations are not designed simply to convey growth into a building—the building is a specific kind of building and has an important purpose. The building is a temple (Ephesians 2:22). In the Old Testament, the temple was designed to be that place where God would meet humanity. It was the house of God (see, for example, the references to the temple as the house of God in 1 and 2 Chronicles). Paul explains that this house of God’s own possession is actually the dwelling place of God. Believers are being built together into a dwelling of God the Holy Spirit (Ephesians 2:22). Because God is Spirit (John 4:24), it makes perfect sense that His dwelling would be a spiritual dwelling, and He lives in believers through the Holy Spirit.
Both Peter and Paul are helping us understand some key implications of our being built up as a spiritual house. First, we are all recipients of God’s grace—while we were dead in sins, God made us alive (Ephesians 2:4–10). Second, because we are all given life by Him, we have equality—we are all living stones who have been made alive in Christ by faith, and in whom the Holy Spirit lives. Third, we have unity because of who God has made us to be (Ephesians 4:3). Because He made us alive and He made us to be one in the body of Christ, we have peace with God (Romans 5:1) and with each other.
The purpose of our being built up as a spiritual house is to form a collective priesthood that is continually offering spiritual sacrifices to God (1 Peter 2:5). But what are the sacrifices that this spiritual house, this priesthood, is bringing to God? Peter doesn’t specify beyond his exhortation that believers live holy lives (1 Peter 1:14–16) and that the sacrifices are spiritual. Paul uses the same terminology of “sacrifice” in Romans 12:1, affirming that, because of the mercies of God, believers should present their bodies a living and holy sacrifice. How wonderful that we are spiritual beings, given new spiritual life and growing up together into a spiritual dwelling of God—and yet, in His grace God allows us to do things of spiritual value with our physical bodies.
What we do with our bodies matters to God, and we can use those bodies to honor our Creator. In doing that, we can keep our behavior “excellent” (1 Peter 2:12, NASB). There is nothing mystical or mysterious about this idea—we are simply designed to use the physical tools God has given us for the purposes for which He has built us. And when we understand that we are designed as a spiritual house and that God lives in us, then we understand that worshipping God means using our bodies to honor and serve Him.