The term “catechism” did not originate in Roman Catholicism as some assume. Rather, the term is derived from the Greek word katecheo, which simply means “to teach or instruct” (Rom. 2:18; 1 Cor. 14:19; Gal. 6:6). Therefore, “to catechize” is simply to instruct in doctrine.
Instruction in doctrine has been the Church’s practice since its earliest days. In the Old Testament, parents were called to instruct their children in both God’s works and His commands (see Deut. 4:9; 6:7; 11:19; Psalm 78). The New Testament Epistles also evidence this careful, thorough instruction. Paul’s Epistles begin by giving instruction in the Gospel (God’s works) and proceed to God’s commands. Once the New Testament canon was completed, ministers adopted this form of instruction to instruct converts and children in the basics of the Christian faith. The Apostles’ Creed was created to summarize the faith and used to prepare adult converts for their baptism.
During the Reformation, catechisms were developed to serve a similar function. They contain a question and answer format to facilitate memorization in adults and, especially, children. After memorizing these basics, a Christian would be far more able to have an intelligent conversation about the Scripture and to understand more of what they believed and why they believed it.
Though many catechisms were produced, the two that have held positions of distinct prominence in Reformed churches are the Heidelberg Catechism and the Westminster Shorter Catechism.