The Three Marks of a True Church

How can you identity the church? Does a group become a church just because it gives itself the name? The Protestant Reformers had to deal with this question because their Roman Catholic detractors claimed (and still claim) that Protestants churches were not churches since they were not in union with the Pope and did not always have bishops who could trace back their ordination in unbroken succession to the apostles. Some Protestants, particularly Anglicans, have contested the second claim about ordination, but many Protestants saw that debate as not worth having, since Scripture does not make the unbroken succession of episcopal ordinations necessary for ordination or the existence of a true church. Since the days of the Reformation, identifying true visible churches has continued to be an issue. Roman Catholics maintain their claims, while many Protestants seem to identify a church as any gathering of Christians (with varying definitions of what it means to be a Christian). 

The Scottish Confession of Faith was written in 1560 by John Knox and five other ministers for the newly reformed realm of Scotland. They addressed this issue directly in their 18th chapter where they discuss the "notes" by which the true "kirk" (the Scottish word for church) is distinguished from false kirks. They denied that the "notes, signs, and assured tokens whereby the immaculate spouse of Christ Jesus" are "antiquity, title usurped, lineal descent, place appointed, nor multitude of men approving an error," giving various examples from the Bible to prove their case. Rather, they went on to articulate three "notes" by which the true kirk could be identified:

"The notes, therefore, of the true kirk of God we believe, confess, and avow to be: first, the true preaching of the word of God, into the which God has revealed himself to us, as the writings of the prophets and apostles do declare; secondly, the right administration of the sacraments of Christ Jesus, which must be annexed unto the word and promise of God, to seal and confirm the same in our hearts;[1] last, ecclesiastical discipline uprightly ministered, as God's word prescribes, whereby vice is repressed, and virtue nourished.[2] Wheresoever then these former notes are seen, and of any time continue (be the number [of persons] never so few, about two or three) there, without all doubt, is the true kirk of Christ: who, according to his promise is in the midst of them:[3] not that universal [kirk] (of which we have before spoken) but particular; such as were in Corinth,[4] Galatia,[5] Ephesus,[6] and other places in which the ministry was planted by Paul, and were of himself named the kirks of God."
1. Eph. 2:20; Acts 2:42; John 10:27; 18:37; 1 Cor. 1:13; Matt. 18:19-20; Mark 16:15-16; 1 Cor. 11:24-26; Rom. 4:11. 2. Matt. 18:15-18; 1 Cor. 5:4-5. 3. Matt. 18:19-20. 4. 1 Cor. 1:2; 2 Cor. 1:2. 5. Gal. 1:2. 6. Eph. 1:1; Acts 16:9-10; 18:1, etc.; 20:17, etc.

A year later (1561), these three marks were also articulated in the Belgic Confession, which was written in the Netherlands and later adopted by many of the Reformed churches on the continent of Europe. In article 29, it declares,

"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.”[1] 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.[2] 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;[3] it makes use of the pure administration of the sacraments as Christ instituted them;[4] it practices church discipline for correcting faults.[5] In short, it governs itself according to the pure Word of God,[6] rejecting all things contrary to it[7] and holding Jesus Christ as the only Head.[8] By these marks one can be assured of recognizing the true church—and no one ought to be separated from it."
1. Rev 2:9. 2. Rom 9:6. 3. Gal 1:8; 1 Tim 3:15. 4. Acts 19:3-5; 1 Cor 11:20-29. 5. Mt 18:15-17; 1 Cor 5:4, 5, 13; 2 Thess 3:6, 14; Tit 3:10. 6. Jn 8:47; Jn 17:20; Acts 17:11; Eph 2:20; Col 1:23; 1 Tim 6:3. 7. 1 Thess 5:21; 1 Tim 6:20; Rev 2:6. 8. Jn 10:14; Eph 5:23; Col 1:18.

It is important to be a member of the church - not only the universal church, but a local assembly of Christians where these three ordinances of Christ are established, with a recognized leadership capable of administering them. Every church will have its errors and faults, but join a church where you can find Christ's ordinances of Word, sacrament, and discipline (which is broader than merely excommunication, but includes discipleship, correction, and admonition, all with the goal of repentance and growth). Of course, these marks are not the entirety of a church - they are the skeleton or the foundation. As Christ works through His appointed means, His people respond in faith and love, engaging in shared worship, mutual edification, and loving help.