I re-read this recently and have been thinking about it a lot ever since:
Chapter IV
The Unity of the Church
1. Since the church of Christ is one body, united under and in one God and Father, one Lord, and one Spirit, it must give diligence to keep this unity in the bond of peace. To this end the church must receive those endued with gifts of Christ as Christ himself, must submit to those whose call to govern in the church has been properly acknowledged, and in particular must learn of those with gifts of teaching the Word of God. Further, since every Christian is endued with some gift for the edification of the body, he must minister this gift to the church as a faithful steward. Church government must maintain this fellowship in Christ and in the gifts of the Spirit and seek its restoration when it has been disrupted through schism.
2. It is the right and duty of those who rule in the church of God to maintain order and exercise discipline, for the preservation both of truth and duty. These officers and the whole church must censure or cast out the erroneous or scandalous, always observing the requirements of the Word of God, and seeking the honor of Christ's name, the good of his church, and the reclamation of the offender.
3. The manifestation of the unity of the church requires that it be separate from the world. Apostasy in faith and life is destructive of the fellowship in Christ; only by rejecting such error can Christian fellowship be maintained. There are many antichrists, many false apostles and teachers. From these the church must turn away, and those who steadfastly hear the voice of false shepherds and follow them cannot be regarded as the sheep of Christ. There are organizations which falsely call themselves churches of God, and others which once were churches, but have become synagogues of Satan. Communion with such is spiritual adultery and an offense against Christ and his saints.
4. The visible unity of the Body of Christ, though not altogether destroyed, is greatly obscured by the division of the Christian church into different groups or denominations. In such denominations Christians exercise a fellowship toward each other in doctrine, worship, and order that they do not exercise toward other Christians. The purest churches under heaven are subject both to mixture and error, and some have gravely departed from apostolic purity; yet all of these which maintain through a sufficient discipline the Word and sacraments in their fundamental integrity are to be recognized as true manifestations of the church of Jesus Christ. All such churches should seek a closer fellowship, in accordance with the principles set forth above.

Form of Government: The Orthodox Presbyterian Church
We're the Orthodox Presbyterian Church. Our purpose is simple: to bring glory to God through our churches and individual lives to make known t...