Shorter Catechism Q. 39. What is the duty which God requireth of man? A. The duty which God requireth of man is obedience to his revealed will.
Commentary: The catechism may be divided into two broad sections. The first section (questions 4-38) deals with what we are to believe, and the second one (questions 39-107) focuses on our duty (see the commentary on WSC 3). We are, therefore, turning a corner in our study with question 39 by transitioning from faith to practice, from creed to conduct.
This question is built upon the doctrine of the preceding section. God created all things, including man, whom he created in his own image in knowledge, righteousness and holiness (WSC 9-10). Two important truths stem from this. First, God is the governor of his creation. All creatures are under his authority and rule (WSC 11). Second, human beings are moral and responsible creatures who owe allegiance and obedience to God their creator. God, therefore, has the right to impose a duty upon man and man is bound to fulfill his God-given duty. Since God exercises his right (WSC 12, WCF 19) the question is: what is the duty which God requires of man?
God requires obedience. Obedience involves the “what” and the “why.” It is as much a matter of the heart as it is a matter of the act. To obey is to do whatever is commanded or required. This is the “what,” and it includes our whole being: desires, words, attitudes, deeds, etc. To obey, also, is to do what is commanded because it is commanded. This is the “why.” We obey because of God, for God and unto God.
God requires obedience from man, that is, all humanity. Christians are not the only ones who must obey God. People with a copy of the Bible, and thus a copy of God’s law, are not the only ones who must obey God. All persons in every generation must obey God.
God requires obedience to his revealed will. We are not expected to obey something we don’t know. Nor should we seek to keep prophecy, or God’s plan (decree). Our duty is to do what God has said (revealed) he wants us to do (will).
For example, God planned before the foundation of the world that a close friend would betray the Christ, and he revealed this plan in the Old Testament. Moreover, Jesus mentioned it to his disciples, including his betrayer Judas, shortly before it happened. Judas, however, was not required to betray the Lord. The opposite was true. His God-given duty was to trust, love and follow Jesus, not hand him over to his enemies. Our duty is not to obey God’s eternal plan (decree) but to obey his revealed will.