Presbyterian and Reformed confessions on the doctrine of the Church are surprisingly complementary.
Article 29: Of the Marks of the True Church
We believe that we ought to discern diligently and very carefully from the Word of God what is the true church, for all sects which are in the world today claim for themselves the name of church. We are not speaking here of the hypocrites, who are mixed in the church along with the good and yet are not part of the church, although they are outwardly in it. We are speaking of the body and the communion of the true church which must be distinguished from all sects that call themselves the church.
The true church is to be recognized by the following marks: It practises the pure preaching of the gospel. It maintains the pure administration of the sacraments as Christ instituted them. It exercises church discipline for correcting and punishing sins. In short, it governs itself according to the pure Word of God, rejecting all things contrary to it and regarding Jesus Christ as the only Head. Hereby the true church can certainly be known and no one has the right to separate from it.
Those who are of the church may be recognized by the marks of Christians. They believe in Jesus Christ the only Saviour, flee from sin and pursue righteousness, love the true God and their neighbour without turning to the right or left, and crucify their flesh and its works. Although great weakness remains in them, they fight against it by the Spirit all the days of their life. They appeal constantly to the blood, suffering, death, and obedience of Jesus Christ, in whom they have forgiveness of their sins through faith in Him.
The false church assigns more authority to itself and its ordinances than to the Word of God. It does not want to submit itself to the yoke of Christ. It does not administer the sacraments as Christ commanded in His Word, but adds to them and subtracts from them as it pleases. It bases itself more on men than on Jesus Christ. It persecutes those who live holy lives according to the Word of God and who rebuke the false church for its sins, greed, and idolatries.
These two churches are easily recognized and distinguished from each other.
I. 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 fulness of Him that fills all in all.
II. 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; and of 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.
III. 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 does, by his own presence and Spirit, according to his promise, make them effectual thereunto.
IV. This catholic Church has 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.
V. 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.
VI. There is no other head of the Church but the Lord Jesus Christ. Nor can the Pope of Rome, in any sense, be head thereof; but is that Antichrist, that man of sin, and son of perdition, that exalts himself, in the Church, against Christ and all that is called God.