11 Cor 1:2; 12:13; Rom 15:9–12; Rev 7:9; Ps 2:8; 22:27–31; 45:17; Mt 28:19–20; Isa 59:21;
²1 Cor 7:14; Acts 2:39;Rom 11:16; Gen 17:7

The English word ‘church’ probably evolved from the Scottish word ‘kirk’, which in turn is derived from the Greek kuriakov" (kuriakos), meaning ‘of the Lord.’ This word may originally refer to buildings that were dedicated to the Lord’s use. However, the word ‘church’ as used in our English Bible translates the Greek ejkklhsiva (ekklêsia) which in 115 times out of 118 refers to an assembly of people who have been called out of the world to be the Lord’s people.

Studying the Scriptures, we see that the church must be understood in two senses, namely visible and invisible. The church invisible comprises of those who are elect in Christ. It is invisible because we cannot tell who are the elect by observation. On the other hand, the visible church comprises professing believers and their children.

Now, we often think of individual congregations as visible churches. However, we should realise that there is really only one visible church (sometimes known as the Visible Church Universal) comprising "all such as in all ages and places of the world do profess the true religion, and of their children." This Church is represented as an Olive Tree in Romans 11 by the apostle Paul. Using this analogy, local congregations or denominations may be spoken of as branches of the visible church.

No one denomination or congregation may claim to be the Visible Church. However, we should note that not every congregation or denomination that calls itself Christian, is really a true branch of the Visible Church. The apostle Paul speaks of the unbelieving Jews as having been broken off from the olive tree (Rom 11:17) and warns that those who have been grafted into the tree but persist not in the goodness of God will also be cut off (v. 22). We may infer therefore that entire congregations and denominations may also be broken off, or have their candlestick removed (Rev 2:5).

A true branch of the Visible Church according to the general Reformed consensus will bear three marks: (1) Faithful preaching of the Word of God; (2) Faithful administration of the Sacrament; and (3) Faithful exercise of church discipline. Thus a congregation or denomination that teaches heresies or ceases to exercise church discipline will disqualify itself as being a true branch of the church of Christ.

But how does a person become a member of the Visible Church? Our catechism teaches us that he becomes a member by professing faith in Christ and upholding the doctrines of the Christian faith. However, such as profess faith genuinely will seek baptism, which is the badge or ratification of membership in the visible church (see WLC 165).

Now, our catechism also teaches us that children of such as are members of the Visible Church are automatically members of the Visible Church (see 1 Cor 7:14; Acts 2:39; Rom 11:16). Therefore children of believers also ought to be baptised.

We should carefully note that one who is baptised is officially a member of the Visible Church, but is not necessarily a member of the Church Invisible. Nevertheless, the church should regard and address every baptised person as a Christian or a member of the covenant community.

But what if a baptised person (whether he was baptised as an adult or as a child) eventually renounces the faith or falls into scandalous sin from which he would not repent? Well, such a person should be cut off, or excommunicated by the church (Rom 11:22; cf. 1 Cor 5:5; 1 Jn 2:19), and regarded as a "heathen man and a publican" (Mt 18:17).

And what about a member of the church who was baptised as an infant and grows up in the church believing in the Lord? Does he have to join the church afresh? No, he is already a member of the church, though he should now confess his faith publicly and seek to be admitted to the Lord’s Table.