Westminster Confession of Faith Chapter 25
Of the Church
The catholic or universal church, which is invisible, consists of the whole number of the elect that have been, are, or shall be gathered into one, under Christ the head thereof; and is the spouse, the body, the fullness of him that filleth all in all.
The visible church, which is also catholic or universal under the gospel (not confined to one nation, as before under the law), consists of all those throughout the world that profess the true religion, together with their children; and is the kingdom of the Lord Jesus Christ, the house and family of God, out of which there is no ordinary possibility of salvation.
Unto this catholic visible church Christ has given the ministry, oracles, and ordinances of God, for the gathering and perfecting of the saints in this life, to the end of the world; and doth by his own presence and Spirit, according to his promise, make them effectual thereunto.
This catholic church hath been sometimes more, sometimes less visible. And particular churches, which are members thereof, are more or less pure, according as the doctrine of the gospel is taught and embraced, ordinances administered, and public worship performed more or less purely in them.
The purest churches under heaven are subject both to mixture and error; and some have so degenerated, as to become no churches of Christ, but synagogues of Satan. Nevertheless, there shall be always a church on earth to worship God according to his will.
The Lord Jesus Christ is the only head of the Church, and the claim of any man to be the vicar of Christ and the head of the Church, is unscriptural, without warrant in fact, and is a usurpation dishonoring to the Lord Jesus Christ.