But if you had known what this means, "I desire mercy and not sacrifice," you would not have condemned the guiltless. Matthew 12:7NKJ
Question 99 of the Larger Catechism, asks, "What rules are to be observed for the right understanding of the ten commandments?" In its answer the Catechism gives eight rules. Here is the fifth one: "For the right understanding of the ten commandments, these rules are to be observed: 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." Last week we considered how each commandment contains both positive and negative precepts. This week we look at the difference between imperatives and prohibitions and how obedience is to be appropriately and timely rendered.
The first part of this rule states that what God forbids is at no time to be done. It is never OK to sin. When God says "Thou shalt not," it is never right to add "except when…." God's commandments are not suggestions, neither are they to be the subjects of discussions about situational ethics. God's laws tell us what we must always do when appropriate, or what we must not do under any circumstances whatsoever. By definition positive imperatives do not always apply and can temporarily be fulfilled, whereas negative prohibitions are always in force and never satisfied. Thus, all men are perpetually forbidden from sexual sin (Thou shalt not commit adultery), but only the married man can fulfill the command to love His wife. Moreover, every specific act of love by a husband to his wife is a singular act of obedience and satisfaction to the command; though he continues to owe her the love of a husband so long as they are married. Similarly, it is always a sin to rob God, yet the man who tithes his paycheck fulfills the command every two weeks.
On the other hand it is much easier to define refraining from evil as compared with doing good. Thus, a judge and jury can determine when a man has broken the 6th commandment forbidding murder, but who can tell when that man has kept the positive side of the law by loving his neighbor? So also the thief knows when he must be fearful of being caught with stolen goods, but when can a man be certain that he has put forth the required effort to honestly earn his own living? Accordingly, although all of the commandments have both positive and negative aspects, eight of the ten are given in the form of a negative prohibition: "Thou shalt not." These negative prohibitions are never to be done. It is always a sin to have other gods, to take God's name in vain, to murder, etc., and there are never any exceptions to these laws. God's prohibitions define moral evil. Moral evil is the worst thing that can occur. Thus, there can be no circumstances justifying or even allowing moral evil. Physical harm, material loss, even death is preferable to moral evil. Thus, a man is permitted even to kill in self-defense, if that is what it takes to keep his attacker from breaking the commandment against murder.
The second part of this rule, that every particular duty is not to be done at all times, speaks to those positive precepts of God's commandments, which sometimes are required in order to refrain from moral evil. In the Scripture verse above, which was cited by the Westminster Divines as a proof text for this part of the Catechism, Jesus reminds his opponents that God desires mercy and not sacrifice. The Pharisees wanted Jesus' disciples to refrain from plucking grain on the Sabbath, in order to offer to God the "sacrifice" of obedience from even the most miniscule of work on the day of rest. However, the disciples were hungry, and Jesus (God) desired that they be able to eat on the Sabbath rather than that they would have to suffer with hunger. Thus, the 4th Commandment is a good illustration of the principle that not every duty is required at all times. Even though it is our duty to worship and to rest on the Sabbath, it is a higher duty to meet the basic needs of our neighbors. So if you are getting ready to come to worship, and your neighbor's house catches fire, it is your duty to help your neighbor and NOT come to church! May God grant that we would remember this rule so that we would be better able to do what all of God's commandments are designed for: that we would refrain from moral evil and do good.