Belgic Confession (1561)
Article 29: The Marks of the True Church
We believe that we ought to discern diligently and very carefully, by the Word of God, what is the true church—for all sects in the world today claim for themselves the name of “the church.”
We are not speaking here of the company of hypocrites who are mixed among the good in the church and who nonetheless are not part of it, even though they are physically there.
But we are speaking of distinguishing the body and fellowship of the true church from all sects that call themselves “the church.”
The true church can be recognized if it has the following marks: The church engages in the pure preaching of the gospel; it makes use of the pure administration of the sacraments as Christ instituted them; it practices church discipline for correcting faults. In short, it governs itself according to the pure Word of God, rejecting all things contrary to it and holding Jesus Christ as the only Head. By these marks one can be assured of recognizing the true church—and no one ought to be separated from it.
As for those who can belong to the church, we can recognize them by the distinguishing marks of Christians: namely by faith, and by their fleeing from sin and pursuing righteousness, once they have received the one and only Savior, Jesus Christ.
They love the true God and their neighbors, They love the true God and their neighbors, without turning to the right or left, and they crucify the flesh and its works.
Though great weakness remains in them, they fight against it by the Spirit all the days of their lives, appealing constantly to the blood, suffering, death, and obedience of the Lord Jesus, in whom they have forgiveness of their sins, through faith in him.
As for the false church, it assigns more authority to itself and its ordinances than to the Word of God; it does not want to subject itself to the yoke of Christ; it does not administer the sacraments as Christ commanded in his Word; it rather adds to them or subtracts from them as it pleases; it bases itself on men, more than on Jesus Christ; it persecutes those who live holy lives according to the Word of God and who rebuke it for its faults, greed, and idolatry.
These two churches are easy to recognize and thus to distinguish from each other.
The Sufficiency of Scripture
We believe that this Holy Scripture contains the will of God completely and that everything one must believe to be saved is sufficiently taught in it. For since the entire manner of service which God requires of us is described in it at great length, no one — even an apostle or an angel from heaven, as Paul says — 2 ought to teach other than what the Holy Scriptures have already taught us. For since it is forbidden to add to or subtract from the Word of God, 3 this plainly demonstrates that the teaching is perfect and complete in all respects.
Therefore we must not consider human writings — no matter how holy their authors may have been — equal to the divine writings; nor may we put custom, nor the majority, nor age, nor the passage of time or persons, nor councils, decrees, or official decisions above the truth of God, for truth is above everything else.
For all human beings are liars by nature and more vain than vanity itself.
Therefore we reject with all our hearts everything that does not agree with this infallible rule, as we are taught to do by the apostles when they say, “Test the spirits to see if they are of God,” and also, “If anyone comes to you and does not bring this teaching, do not receive him into your house.” Gal. 1:8; Deut. 12:32; Rev. 22:18-19; 1 John 4:1; 2 John 1:10