Necessity of Creeds
The Word of God calls upon believers to confess their faith. Jesus said, Therefore whoever confesses Me before men, him I will also confess before My Father who is in heaven (Matt. 10:32). The apostle Paul concurs: If you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved (Rom. 10:9). To assure a purity of confession, the church has written various creeds over the years. Creeds are universal as summaries of the truth of the gospel.
Even those who proclaim "No Creed but Christ" have a list of propositions that defines the Christ they believe in. The problem is that they are not willing to publish this list since it might change. There should be no fear to publish the teachings of Scripture, though: the Lord got his doctrines right the first time! Nevertheless, as Christians we must agree that, if our creedal summary is in error, we will change it.
The Bible teaches that man's conscience should be bound only by the Word of God (Mark 7:9). This does not lead to anarchy, as one might suppose, because the Bible also teaches the unity of the true faith and separation from those who do not hold to the clear teaching of God's Word (2 Cor. 6:14ff.; 1 Tim. 6:3-5; 1 John 4:1-3; 2 John 10).
Basic Christian unity is confessed by Reformed Christians with all who sincerely hold to the teachings of the Apostles' Creed (see Heidelberg catechism, Questions 22 and 54). Historic confessions have generally used the Apostles' Creed, the Ten Commandments and the Lord's Prayer to structure their more specific doctrinal statements.
Reformed churches, along with other churches descending from the Reformation, have followed the ancient church tradition of writing expository creeds which state Biblical teaching in a way that separates believers from unbelievers (cf. the Nicene Creed, which declares that all Christians must believe in the Trinity). Reformed confessions include the Heidelberg catechism, the Belgic Confession of Faith, the Canons of Dort, the Second Helvetic Confession and the Westminster Standards (the first three creeds constitute the confessional base of the RCUS). These expository creeds serve as the skin and bones for the church as an organization on earth. As bones, they give it a unifying structure, since all members and officers confess the truth of the doctrines they set forth; as skin, they separate those of a particular denomination from others outside the church structure.
Because Reformed churches hold that unity in truth is the basis of all other unity (2 John 10), they form close-knit denominational fellowships and establish ecumenical connections with other Reformed bodies holding similar creeds. Such fraternal relations should not be confused with the modern tendency of church unionism.