Paul describes believers as sealed with the Holy Spirit. A seal fulfills a past promise and pledges a future inheritance. A King’s seal had a three-fold purpose: 1) to guarantee authenticity, 2) to name the rightful owner, and 3) to protect from being tampered with or harmed.
Think about what you’d wish for if you had a genie. Think about what you pray for. How similar are they?
When Paul writes in Ephesians 2 that believers are “growing into a holy temple in the Lord” and “being built together into a dwelling of God in the Spirit”, he’s drawing on rich Old Testament history.