"19 Consequently, you are no longer foreigners and strangers, but fellow citizens with God’s people and also members of his household, 20 built on the foundation of the apostles and prophets, with Christ Jesus himself as the chief cornerstone. 21 In him the whole building is joined together and rises to become a holy temple in the Lord." Ephesians 2:19-21 New International Version

In the same way, God uses the individual members of his body to build His Church, rather like a pyramid that builds one layer on top of another until it is complete.