In the Christian Reformed Church you sometimes hear people talk about the three forms of unity. Those three forms consist of the Belgic Confession, Canons of Dort, and Heidelberg Catechism. All those who serve as Deacons, Elders, and Pastors in the CRC are asked to sign a “Form of Subscription” meaning that they affirm what is written in these three forms.
Belgic Confession: The Belgic Confession, written in 1561, takes pains to point out the continuity of Reformed belief with that of the ancient Christian creeds.
Canons of Dort: The Canons of Dort is a very finely tuned piece of theological writing, ably delineating a biblically Reformed perspective on matters central to Christian life and experience.
Heidelberg Catechism: The Heidelberg Catechism, written in 1563, is a remarkably warm-hearted and personalized confession of faith.