Today we conclude our study on the church by noting that there are many different bodies that call themselves churches, whether or not they are true manifestations of the church of Jesus Christ. How then can we tell when a church in name is also a church in reality?
Faced with this same problem, the Reformers and Roman Catholics answered this question very differently. Rome has said that the bishop is the mark of the church, that is, the true church is present when you have a duly consecrated bishop who is part of a line of succession going back to the apostles. Ultimately, a bishop is a true bishop only if he submits to the pope; thus, in Roman Catholicism only Roman Catholic parishes constitute the true church.
Protestants recognize the biblical failings of this view and, in studying Scripture, traditionally define a true church according to two criteria:
1. The Word — there is no true church without the right proclamation of the Word of God. In other words, a group that denies any of the essential truths of the Christian faith is not a church. The essential truths of Christianity are clearly taught in Scripture, and the Nicene Creed is one document that helpfully summarizes them. A truth like justification by faith alone is included in this list even though it is not specifically mentioned in the creed, because Paul lists it as a defining mark of the Gospel (Gal. 1:6–9; 2:15–16), and it is a necessary deduction from the creed’s emphasis on salvation through Christ alone.
2. The Sacraments — a true church rightly celebrates the Lord’s Supper and baptism. That is, the sacraments must be conducted in line with Scripture’s clear teaching, and we must allow for latitude where such things are not so plain. For example, the biblical instruction on the mode of baptism is not as clear as we might like; thus, we cannot anathematize those who disagree with us in this specific area. Celebrating the sacraments correctly also involves keeping unrepentant sinners from partaking in these means of grace (church discipline). Though inseparably linked to the sacraments, sometimes we make special mention of church discipline as the third mark of the church (1 Cor. 5).
First Corinthians 11:17–34 gives us the marks of the church specifically and through good and necessary deduction. The whole passage concerns the Lord’s Supper, a reference to the sacraments. Paul also gives the words of institution, a reference to the Word of God since these words were first spoken by Jesus. How highly do you value these means of grace and marks of the church? They are necessary for your spiritual growth and maturity.