What is the foundation of your moral principles?

If you consider that a simple question, you’ve never really thought about it much.

The gut reaction of most Protestants would be “Scripture”—certainly a fitting place to begin—but when one drills down into the details, things get complicated rather quickly. For decades, theological liberals have dismissed biblical teaching on sexuality because they dismiss the Bible. In more recent years, a newer contingent rejects traditional Christian teaching on sexuality arguing that “the Bible never taught it in the first place.”

One purpose of apologetics is to defend Christian teaching before a skeptical, hostile world that cares nothing about what the Bible does or does not say. But discipleship begins at home, and by all measures the Western Church is failing. Sex has a great deal to do with it. On one hand, unmarried adults who are sexually active are far less likely to attend services. On the other, many young people raised in the church experience a crisis of faith when, on embracing the secular narrative, they come to see Christianity as not merely anachronistic but immoral.

“It’s not science that’s secularizing Americans — it’s sex.”
—Mark Regnerus, The Washington Post, September 5, 2017

A comprehensive sexual apologetic must begin with the church family. Let us begin by considering two traditional objections against biblical teaching on sexuality.

Objection 1: “What about the Old Testament prohibition against _____?” [fill in the blank]

Many Christians, perhaps most, view biblical law as akin to the U.S. and state criminal codes: a comprehensive attempt to define and categorize every important wrong one can commit against others or the state. Yet, if we assume that is the case, we immediately run into problems. Where was the law prior to Moses? What was the law outside of ancient Israel? Why were there no prohibitions against slavery or polygamy? And what about all the weird ones? These questions may seem quite challenging, but the answer is simpler than you think. For that we should begin with how the great medieval theologian Thomas Aquinas explained the matter.

Aquinas divided law into four categories. The first, Eternal Law, reflects the mind and desire of God concerning the behavior of humankind and the universe. The universe, of course, obeys. Humanity, not so much. Eternal Law is what all believers should aspire to obey but is beyond our apprehension.

The second, Natural Law, is the will of God imprinted upon the minds of all people in all places in all times. It is manifested in a universal God-consciousness, the universality of conscience and the general consistency of moral principles across most human civilizations. As history attests, Natural Law can easily be resisted, suppressed or ignored.

The third, Divine Law, can also be called the Revealed Law, and we will refer to it as such. The Revealed Law, as found in the Old Testament, expresses Eternal Law (the mind of God) and codifies Natural Law, but with some major caveats. Importantly, Mosaic Law included much that was clearly of ceremonial or civil intent pertaining to the worship and governance of ancient Israel. Those elements did not overlap with Natural Law, and merely expressed Eternal Law as it applied to the nation of Israel.

The fourth category of Aquinas, Human Law, would consist of ordinances created by human agents. Theologically, we predict that it would reflect the existence of Natural Law, which in fact it does.

If one imagines the Mosaic Law as a comprehensive code, it had significant shortcomings. The Old Testament never specifically proscribed prostitution* or slavery, but every time they are mentioned, it is in a disapproving way. Is that not sufficient to know they are wrong? The Old Testament never explicitly proscribed premarital sexual intercourse. If it happened, the law simply demanded that the man must pay the bride-price and marry her (Exodus 22:16). Mosaic Law never proscribed polygamy. Adultery was a one-way street: if a married woman slept with another man, it was adultery. If a married man slept with another women, it was permitted if she were not married or betrothed to another, though he would still have to marry her. [By New Testament times, after polygamy ended, the definition of adultery became more symmetric and inclusive]. These examples demonstrate that the Mosaic Law was never intended to be comprehensive; not that such things were acceptable because they were not prohibited.

Christians are privileged to receive clarification on the Mosaic Law through the ministry of Jesus and the apostles. When Jesus spoke of the Mosaic Law, He judged the Pharisees not for their lack of conformity to the Mosaic Law, but to Eternal Law. Hence, on the one hand He could judge them for being too literal in its interpretation (their rules on the Sabbath or divorce), and on the other for thinking mere outward compliance was good enough (declaring lust as equivalent to adultery). At the Jerusalem Council described in Acts 15, the apostles, under the inspiration of the Holy Spirit, ruled that Gentile converts were not subject to the Mosaic Law, but:

“Instead we should write to them, telling them to abstain from food polluted by idols, from sexual immorality, from the meat of strangled animals and from blood” (Acts 15:30, NIV 1984).

Without an understanding of Natural Law, this appears to make no sense. Other than refraining from sexual immorality (funny how that keeps popping up) and three dietary restrictions (probably to maintain peace between Jews and Gentile converts), the entire Mosaic Law was just abolished? Of course not. While Christians were no longer under the Mosaic Law, they remained bound by Eternal Law and Natural Law. Lest there be any uncertainty concerning those obligations, the New Testament reaffirms and elaborates on the demands of Eternal Law through the commandments of Jesus and the instruction of the apostles (establishing a new Revealed Law for future generations). Many believe the Ten Commandments remained in effect. This approach, however, is not without its problems. According to the Westminster Larger Catechism, the Jesus Film would be in flagrant violation of the Second Commandment, and any sort of recreation on Sunday violates the Fourth Commandment (questions 109 and 119).

When we understand the preeminence of Eternal Law, it makes complete sense to declare that “love is the fulfillment of the law” (Romans 13:10b, NIV 1984), without the ludicrous inference that love is the only law.

Christian moral principles are based upon the Eternal Law of God as understood through Natural Law and explicitly affirmed by Jesus and the apostles. The Mosaic Law is not relevant to this discussion, and the Christian apologist should not rely on it in evidence. While this may seem controversial, it is consistent with the historic teaching of most major Christian traditions. We are not “throwing out” the Old Testament, as some might charge. Old Testament wisdom and historical narrative, as well as prophecy and Psalms, remain an integral part of Christian theology and experience. The crucial moral elements of Mosaic Law are subsumed under Natural Law and the Revealed Law of the New Testament.

Objection 2: “On matters of sex, the New Testament writers were merely accommodating the cultural biases of first century Palestine.”

This argument sounds plausible enough except for the word “accommodating.” That word reverses the flow of information in a fundamental way. It implies, without evidence, that moral teaching was not delivered to the “masses” but derived from them. According to this narrative, God really would have liked to liberate those early Christians from their sexual hang-ups, but they were just too primitive and barbaric.

Of course, that is all complete nonsense. The early Christians (and Jews) were hardly different from those in the West today—a devoutly religious minority surrounded by a licentious, pagan majority. Christian sexual teaching was certainly in conformity with Jewish tradition, and Jesus and the apostles all assumed a common acceptance of these principles. But in the broader society, Christian teaching was decidedly countercultural.

Now, there are legitimate instances in which certain New Testament instructions—I hesitate to call them commands—are socially constructed. A traditional example of this would be Paul’s extended riff on head coverings in 1 Corinthians 11:1-16. This has been almost universally understood as a specific application of a much more general principle: when gathering in worship, men and women should attire themselves in a manner appropriate to their sex as understood in their own culture. As explained by R.C. Sproul, “Principles are those commands of God that apply to all people at all times in every culture…Customs are local applications of those principles.”

Many such minor matters come up in the writings of Paul, who was busily occupied with teaching early Christians how to behave and get along. We can infer their moral significance by the degree to which they are, or are not, framed in moral terms. In Matthew, Jesus warned, “For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies. These are the things which defile a man, but to eat with unwashed hands does not defile a man” (Matthew 15:19-20, NKJV). In Romans 1:28-32, Paul describes the reprobate as “…filled with all unrighteousness, sexual immorality, wickedness, covetousness, maliciousness; full of envy, murder, strife, deceit, evil-mindedness; they are whisperers, backbiters, haters of God, violent, proud, boasters, inventors of evil things, disobedient to parents, undiscerning, untrustworthy, unloving, unforgiving, unmerciful…” (NKJV). Nowhere will one find Paul’s instructions regarding the conduct of worship or church governance couched in such language. They are altogether in a different category. All commands of the law are instructions, but not all instructions are commands of the law. Hopefully, the passages we have considered here help to illumine the distinction.

In my next post, we will look at two more contemporary objections raised to Christian sexual morality. Is it all based on a mistranslation of New Testament Greek? Has Christian sexual morality been refuted by modern science?

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*Leviticus 19:29a says, “Do not degrade your daughter by making her a prostitute,” but it didn’t prohibit her from entering voluntarily (NIV 1984).

For a concise, easily accessible introduction to Natural Law from a Protestant perspective, see Natural Law: A Brief Introduction and Biblical Defense by David Haines and Andrew A Fulford.