Theologians sometimes take commonly used terms and redefine them for a special use.
Presbyterians have been known to take “equity”, (once a very common legal term) and use it in ways different from historic usage. That can cause a bit of confusion. In the time of the writing of the confession and catechisms the use of “Equity” in regard to law and ethics was very common. The common law courts were thought of as limited and expensive, such that justice itself was often voided through simply following of ‘stare decisis’ and few available options for remedies.
In the 14th century (we need to remember that we adhere to an English confession adopted by a Scottish nation now received by a largely Dutch-American Church and this can distance us from the original interpretation of the confessional standards) Courts of Chancery and Courts of Equity were created specifically for the purpose of arriving at “equity” when the laws were insufficiently complex to respond to circumstances. Getting to equity meant in the simplest sense getting to justice when the laws were inadequate to the task. Justice meant every man receiving his due.
The Westminster Confession of Faith 19-4 reads as follows, the question being to what extent to the laws of Israel as a political people have continuity today.
“To them also, as a body politic, he gave sundry judicial laws, which expired together with the State of that people; not obliging any other now, further than the general equity thereof may require. WCF 19-4
The document of our confessional standards that explains equity in an almost painfully clear detail is the larger catechism, that goes on section after section laying out detailed explanations of equity.
“HAVING SEEN WHAT THE SCRIPTURES PRINCIPALLY TEACH US TO BELIEVE CONCERNING GOD, IT FOLLOWS TO CONSIDER WHAT THEY REQUIRE AS THE DUTY OF MAN
Q. 91. What is the duty which God requireth of man?
A. The duty which God requireth of man, is obedience to his revealed will.
Q. 92. What did God first reveal unto man as the rule of his obedience?
A. The rule of obedience revealed to Adam in the estate of innocence, and to all mankind in him, besides a special command not to eat of the fruit of the tree of the knowledge of good and evil, was the moral law.
Q. 98. Where is the moral law summarily comprehended?
A. 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.
Q. 100. What special things are we to consider in the Ten Commandments?
A. We are to consider, in the Ten Commandments, the preface, the substance of the commandments themselves, and several reasons annexed to some of them, the more to enforce them.”
The Larger Catechism explains commandment by commandment those principles of law, their manifold applications, the reasons for the laws, and does this for the purpose of our opportunity to enforce them.
Someone once said that the term “equity” arises only one time in the WLC, and that would be true, but first, the idea is present in an ongoing fashion and was not at the time thought to demand necessary repetitions, and second, when it is used it is used in the same sense as in the WCF 19-4.
“Q. 120. What are the reasons annexed to the fourth commandment, the more to enforce it?
A. The reasons annexed to the fourth commandment, the more to enforce it, are taken from the equity of it, God allowing us six days of seven for our own affairs, and reserving but one for himself, in these words, Six days shalt thou labor, and do all thy work: from God’s challenging a special propriety in that day, The seventh day is the sabbath of the LORD thy God: from the example of God, who in six days … made heaven and earth, the sea, and all that in them is, and rested the seventh day: and from that blessing which God put upon that day, not only in sanctifying it to be a day for his service, but in ordaining it to be a means of blessing to us in our sanctifying it; Wherefore the LORD blessed the sabbath day, and hallowed it.”
This taken in the obvious and historic sense of the term carries the old presumption of the continuity of the moral aspects of the law regardless of the covenantal administration. Justice, equity, is not changing and reflects the eternal and unchanging nature of the God that brought all things into being and to the extent that a given law is an expression of equity that law is binding upon the Christian conscience. Though the law of Moses did carry ceremonial and judicial forms peculiar to the tutorial light of the old administration of the covenant of grace, the institutionalization of the moral law did not invalidate the moral law, but serves as its revelation.
The judicial laws were binding upon that people, and are binding upon us in so much as they are expressions of the moral law, of equity, but no more than that. If we were not to adhere to the morality of the judicial laws we would likely avoid any ethical judicial action whatsoever, being that the ethics of God and His justice were revealed with such vigor in his intimate dealings with the people of the covenant in that historical context.
As for the question of whether equity in the confession is identical to the “natural law”, of course it is, because the natural law is identical to the moral law, and the moral law is identical to the ten commandments of God. If one wants to measure morality by the laws of nature, that’s good, if one indeed knows and can measure what those laws of nature are, and it seems that the most clear revelation of the natural laws are found in sacred scripture, the avoidance of scripture in identifying and applying the natural law being one of the foremost causes of inequity and injustice in the history of our kind.
As for the use of equity and the light of nature as being expressions of moral continuity, consider the following:
“Q. 121. Why is the word Remember set in the beginning of the fourth commandment?
A. The word Remember is set in the beginning of the fourth commandment, partly, because of the great benefit of remembering it, we being thereby helped in our preparation to keep it, and, in keeping it, better to keep all the rest of the commandments, and to continue a thankful remembrance of the two great benefits of creation and redemption, which contain a short abridgment of religion; and partly, because we are very ready to forget it, for that there is less light of nature for it, and yet it restraineth our natural liberty in things at other times lawful; that it cometh but once in seven days, and many worldly businesses come between, and too often take off our minds from thinking of it, either to prepare for it, or to sanctify it; and that Satan with his instruments much labor to blot out the glory, and even the memory of it, to bring in all irreligion and impiety.”