In Ephesians 2:19-20, Paul clearly gives the meaning of a Christian as a "member of the household of God, built upon the foundation of the apostles and prophets, with Christ Jesus Himself being the cornerstone".
Such a meaning has three components and the very first is to be a member of the household of God.
Membership requires a process that usually starts with an application as proof of intent or interest to join by the applicant, followed by an interview and/or orientation that serves as the framework for the relationship that will exist between the applicant and the entity he wishes to join. The final process is the acceptance of the applicant as a member of the entity where he takes an oath. In this case, a person is accepted as a member of the household of God through Baptism.
The second component describes the household of God or simply put, His Church. Paul clearly stated that God's church is one that is built upon the foundation of the apostles and prophets.
Any house without a strong foundation will eventually collapse. It's foundation must be strong and solid to withstand any force, tried and tested for all time, and continue to stand until today up to all generations that will follow. God's true church is the church that has been in existence for centuries and established by the apostles themselves.
The third and final component describes the religion of the true church of God, and that is "with Christ Jesus Himself being the cornerstone".
As Paul placed it, "Those who are separated from Christ are strangers to the covenants of promise, having no hope and without God in the world". Christ Jesus made us all one, breaking down the dividing wall between God and men. His own flesh and blood reconciled us to God and through Him, we now have access in one Spirit to the Father.
