How do we know the church is God's spiritual kingdom?

The New Testament reveals that the true church represents God's spiritual kingdom, not bound by physical location or ethnicity but unified in faith through Christ. Galatians 3:26-29 and Titus 2:14 affirm that all believers, regardless of their earthly ties, become part of God's chosen people through faith in Jesus. Additionally, 1 Peter 2:9 describes the church as a royal priesthood, indicating that believers are called to serve and worship God. The measuring of the temple in Revelation illustrates this spiritual reality, emphasizing that God's grace and the efficacy of Christ's sacrifice define the dimensions of His kingdom and the identity of the church as His beloved, holy people.