No Other Gods

As we begin to study the Ten Commandments as they are presented in Deuteronomy 5 and exposited by the Heidelberg Catechism, let us first consider its approach to these rules. When the catechism looks at a commandment, it covers both what the commandment forbids and what it commands. This might seem strange, for these commandments come to us as either simple prohibitions or positive edicts. For example, the first commandment is a simple negative, a prohibition: "You shall have no other gods before me" (Deut. 5:7). Yet in expositing this rule, the Heidelberg Catechism says this commandment also orders us positively to trust God alone (Q&A 94). How can it do this?

First, reading God's law this way reflects the way that all laws are designed. For example, if a law forbids me from driving more than 35 miles per hour on a given road (a negative—what not to do), it necessarily follows that I must drive 35 miles per hour or less on the same road (a positive—what to do). We rightly read God's law only if we consider both the negative and the positive sides of a command.

Second, the Ten Commandments' relation to the rest of the Mosaic law shows that each commandment covers more than what it states explicitly. The Ten Commandments are what we call apodictic laws, which are unconditional statements that apply universally to all people. They are simple and self-evident. Casuistic law, or case law, on the other hand, explains how apodictic laws apply to specific individuals. For example, an apodictic command such as "you shall not murder" (Deut. 5:17) is applied to specific instances of killing by the case laws of Numbers 35:9–34. The Mosaic law is full of case law that reveals the Ten Commandments' full significance and application.

Finally, the Lord Jesus Christ Himself shows us that searching out the broader applications and implications of God's commandments is the right way to interpret and understand His law. Matthew 5:21–30, for example, tells us that the commandments against murder and adultery also prohibit that which may lead to those sins, namely, unjust anger and lustful thinking. The Ten Commandments, then, address the heart as well as outward behavior. In fact, all sin begins within the heart. We begin to obey the Lord rightly only when our hearts are intent on loving Him above all else. This is part of what God tells us when He forbids idolatry.