You seem to overlook Romans ch 8.. the church is a spiritual entity.. for “You MUST be born again”- Jesus.. and then be called “OUT OF” the sheep pens( John ch10).. (EKlesia- i.e. church)..
The christians addressed in this letter were already members of the Church and had been "born again" through the Sacrament of Baptism. Paul's Letter to the Romans is a powerful exposition of the doctrine of the supremacy of Christ and of faith in Christ as the source of salvation. It is an implicit plea to the Christians at Rome, and to all Christians, to hold fast to that faith. They are to resist any pressure put on them to accept a doctrine of salvation through works of the law (see the note on Romans 10:4). At the same time they are not to exaggerate Christian freedom as an abdication of responsibility for others (Romans 12:1-2) or as a repudiation of God's law and will.
In John 10:16, Jesus says there must only be one flock and one shepherd. This cannot mean many denominations and many pastors, all teaching different doctrines. Those outside the fold must be brought into the Church. And in John 17:11,21,23, Jesus prays that His followers may be perfectly one as He is one with the Father. Jesus' oneness with the Father is perfect. It can never be less. Thus, the oneness Jesus prays for cannot mean the varied divisions of Christianity that have resulted since the Protestant reformation. There is perfect oneness only in the Catholic Church.