Westminster Larger Catechism (Q 98-99)

Dear Church Family,

This past Sunday, we continued our Sunday school lessons in the Westminster Larger Catechism (WLC) in questions 98-99. Here is a brief review.

WLC 98  Where is the moral law summarily comprehended?
The moral law is summarily comprehended in the ten commandments, which were delivered by the voice of God upon Mount Sinai, and written by him in two tables of stone; and are recorded in the twentieth chapter of Exodus. The four first commandments containing our duty to God, and the other six our duty to man.

In a previous lesson, we learned of the three main kinds of law that we find in Scripture: moral, ceremonial, and judicial. Here, we learn that the moral law is summarily comprehended in the ten commandments. That is to say, the ten commandments which were given by God to the people of Israel on Mount Sinai (Exodus 20) are the summary of God’s eternal moral law.

The WLC notes that the ten commandments were recorded on two tables of stone and that the first four commandments contain our duty to God, while the other six contain our duty to man. Many scholars believe that the two tablets of stone were actually two copies of the same commandments. According to the suzerain/vasal treaties of the ancient near east, one copy of the covenant was to go with the suzerain (in this case, God) and the other with the vasal (in this case, Israel); however, both copies were placed in the ark of the covenant to show that God was going with Israel (Deuteronomy 10:1-5).

WLC 99  What rules are to be observed for the right understanding of the ten commandments?
For the right understanding of the ten commandments, these rules are to be observed: 1. That the law is perfect, and bindeth everyone to full conformity in the whole man unto the righteousness thereof, and unto entire obedience for ever, so as to require the utmost perfection of every duty, and to forbid the least degree of every sin. 2. That it is spiritual, and so reacheth the understanding, will, affections, and all other powers of the soul; as well as words, works, and gestures. 3. That one and the same thing, in divers respects, is required or forbidden in several commandments. 4. That as, where a duty is commanded, the contrary sin is forbidden; and, where a sin is forbidden, the contrary duty is commanded; so, where a promise is annexed, the contrary threatening is included; and where a threatening is annexed, the contrary promise is included. 5. That what God forbids, is at no time to be done; what he commands, is always our duty; and yet every particular duty is not to be done at all times. 6. That under one sin or duty, all of the same kind are forbidden or commanded together with all the causes, means, occasions and appearances thereof, and provocations thereunto. 7. That what is forbidden or commanded to ourselves, we are bound, according to our places, to endeavour that it may be avoided or performed by others, according to the duty of their places. 8. That in what is commanded to others, we are bound, according to our places and callings, to be helpful to them; and to take heed of partaking with others in what is forbidden them.

WLC 99 lists eight rules that we ought to observe for the right understanding of the ten commandments. In class, we spent some time going over and discussing these rules and how we should properly apply them. Here, we will simply summarize these eight rules:

(1) Exacting: the commandments bind everyone to full conformity and require utmost perfection (James 2:10).

(2) Extensive: the commandments are spiritual (Matthew 22:37-38), and therefore reach the soul (understanding, will, affections, etc.) and body (words, works, and gestures).

(3) Overlapping: things are often required or forbidden in several commandments (1 Timothy 6:10).

(4) Reciprocal: in the commandments, duties are commanded (prescribed) and forbidden (prohibited) and promises and threatenings are added (Ephesians 4:28).

(5) Unbending: what God forbids ought never to be done, and what God commands is always our duty; situational ethics, consequentialism, or “the ends justify the means” are not options regarding God’s law (Hebrews 11:24-26).

(6) Comprehensive: under one sin or duty, all others of the same kinds are forbidden or commanded (Matthew 5:21-22, 27-28).

(7) Neighborly Service: “helping others to do what is commanded to us” – as we seek to keep God’s law, we ought to endeavor to help and not hinder others in keeping the law (Exodus 20:10; Deuteronomy 6:6-7).

(8) Role Responsibility: “helping others to do what is commanded to them” – as we recognize our differing roles and responsibilities, we ought to endeavor to help others keep the law as it is specifically applied to their station in life (2 Corinthians 1:23-24; 1 Timothy 5:22).


Some of these eight rules for rightly understanding and applying the ten commandments are things that we automatically do and understand. Yet, there are others which cause us to think about the law of God in ways that we had not previously done. This is one of the benefit of studying the Westminster Larger Catechism; the catechism gives us biblical rule of interpretation and divine categories for understanding God’s law.

Join us on Sunday mornings at 9:15 am as we learn more of how we may offer up our thankful obedience to our Savior in all that we think, say, and do.

The Lord be with you!
Pastor Peter M. Dietsch