“Consequently, you are no longer foreigners and aliens, but fellow citizens with God’s people and members of God’s household.”
Let us pretend there is a nation called Occland and we want to become a citizen of that nation. Of course citizenship would not be automatic. And in the same way, citizenship in the Kingdom of God (being a Christian) is not automatic.
Just living in a Christian nation does not automatically make us a Christian any more than just living in Occland would automatically make us a citizen.
Owning a Bible does not automatically make us a Christian any more than owning a copy of Occland’s constitution would automatically make us a citizen.
Going to church meetings every Sunday does not automatically make us a Christian any more than going to Occland’s meetings of parliament or the senate would automatically make us a citizen.
It just is not automatic. We would need to be invited into Occland, and then do things to accept Occland’s invitation. God invites us into his kingdom, but we must do things to accept his invitation. Romans 6, Acts 2 and 1st Peter 3:21 in the New Testament are good places to check it out. Do so.
God has already done the hard part. Our part is easy ~ our part in accepting his invitation to be citizens in his kingdom.