Opponents of ethical naturalism may argue that consequentialism and utilitarianism are constructs of man that presuppose ‘reason’ and other ‘enlightenment’ values, sidestepping metaphysics and divinity. But the Bible is a creation of man and is interpreted by man. All forms of law (natural, positive, and divine) are anthropic, to varying degrees . On a related note On the Unhappy Consciousness of Neoreactionaries:
This quarrel over the Enlightenment resonates with a debate that raged during the European Enlightenment. On one side were radical thinkers such as Diderot, d’Holbach, Paine, Jefferson, and Priestley—philosophers and Unitarians who attacked the Church and the monarchy and saw the progress of reason as the realization of universalism. On the other side were more moderate Enlightenment thinkers such as Ferguson, Hume, and Burke, who championed the monarchical-aristocratic order of society. The Enlightenment, it would seem, has no original commitment to democracy. On the contrary, the issue was contested from the start.
That’s where the ‘middle ground’ comes into play between the Enlightenment and total rejection of it. But a counter argument is that any concession or relinquishment of ‘total power’, no matter how small or gradual, eventually leads to full-blown liberalism (which some call the ‘progressive singularity’).
The denial of an innate moral ‘code’ seems like another version of ‘blank slate’, except applied to morality instead of IQ. The evidence suggests a large element of human behavior is congenital.  Some people are ‘wired’ poorly, but that’s what jails are for (invoking consequentialism). Some people can be rehabilitated; other’s cannot.
From Christopher Hitchens:
“I think our knowledge of right and wrong is innate in us. Religion gets its morality from humans. We know that we can’t get along if we permit perjury, theft, murder, rape, all societies at all times, well before the advent of monarchies and certainly, have forbidden it… Socrates called his daemon, it was an inner voice that stopped him when he was trying to take advantage of someone… Why don’t we just assume that we do have some internal compass?”
Ants don’t have a moral code, yet ant colonies are self-sustaining and cooperative.
That does not render religion and law useless–they provide guidelines for how people should behave, but cannot account for all of behavior. There are probably two levels of morality: innate morality that covers the basics such as not to steal, not to inflict physical harm on others, etc.; second, prescriptive ethics and morality for things that are less obvious and or seemingly arbitrary (for example: Islamic and Jewish dietary laws, taxation, etc.).
Babies aged six months old have already developed a strong moral code, according to psychologists. They may be barely able to sit up, let alone take their first steps, crawl or talk, but researchers say they can still tell the difference between good and evil.
An astonishing series of experiments is challenging the view that human beings are born as ‘blank slates’ – and that our morality is shaped by our experiences.
 In the context of Divine law, codified by Aquinas, moral precepts are teleological, which means human action are inextricable from the will of God, in contrast to natural law and social contract theory, both of which limit and reduce to varying extents the power of kings and the role of God (a social contract may or may not be theistic and monarchical. Rousseau, a political philosopher of the Enlightenment, advocated a social contract theory that argued that power should be held in the hands of people, who are sovereign, not kings).
Natural law is related to the social contract theory and the Enlightenment, but natural law and social contracts are not necessarily the same thing, although they are often confused. Natural law is a form of social contract, but not all social contrasts involve natural law. Hobbes advocated a contractual, positivist version of law, witting in Leviathan “a precept, or general rule, found out by reason, by which a man is forbidden to do that which is destructive of his life, or takes away the means of preserving the same; and to omit that by which he thinks it may best be preserved.” But in the case of Hobbes, in contrast to divine law, rather then law serving God, it’s for individual self-preservation to avoid a violent death at the hands of another. The social contract theory of Locke, which assumes human are rational and have free will, endows individuals with unalienable rights (natural law). Hobbes’ social contract proscribes natural rights and assumes humans have no intrinsic moral goodness and that humans must submit to the sovereign for there to be stability, which is related to legal positivism (man-made laws).