No, and yes. One of my favorite writers, CS Lewis, in one of my favorite books, The Abolition of Man, makes a very bad argument for a very bad understanding of natural law. The entire last third of the book is devoted to an exposition of the Tao, which he describes as a universal moral law by which God Himself is bound. The notion that there is a law, or anything above God, to which He must submit is heretical, broadly speaking a form of idolatry. There is no law above God. He alone is a law unto Himself. In this sense there is no such thing as natural law.
All law is God’s law. It flows out of His own character. It is neither above Him, such that He must submit, nor below Him, such that He can act capriciously. He instead acts consistently with who He is. This is what we mean when we note that God is a law unto Himself.
The God who is, the God of the Bible, however, has revealed Himself, and at least some elements of His law not just in the Bible, but in His creation, through nature. If by natural law we mean, “That law, which the triune God of the Bible reveals in and through His creation” we are speaking of something altogether real. Romans 1 clearly teaches that God is manifest to all men everywhere, and that all men everywhere in themselves reject that revelation, and thus stand guilty before God.
It is not, however, just God that is revealed. His law is revealed as well. There are those, however, who in an admirable zeal to combat the error of CS Lewis, who with an honorable passion to protect the glory of God’s revelation of law in His Word, try to deny that God reveals law in nature. They tend to treat natural law and revealed or Biblical law as if they were competing with each other. If natural law increases, they seem to think, Biblical law decreases. And if we can sufficiently honor Biblical law, natural law will disappear.
There is a profound problem with this position, however. The problem isn’t that it pushes against natural law, but that it denies what the Bible clearly teaches. I have been known, when engaged in debate with these good folks, to offhandedly offer this instance of “natural law”- “Nature teaches that it is a shame for a man to have long hair.” Some, sadly insufficiently mindful of the Bible they seek to protect, retort, “Where? How? What is it in nature that expresses such a law?” Then I get to give one of my favorite answers- “I don’t know.”
I do know, however, that the Bible says just that. No, the Bible doesn’t teach that it is a shame for a man to have long hair. The Bible teaches that nature teaches that it is a shame for a man to have long hair- Does not even nature itself teach you that if a man has long hair, it is a dishonor to him? I Corinthians 11:14.
Natural law, generally speaking, is not as clear as God’s Word. It is not, generally speaking, as specific as God’s Word. But like God’s Word, it is a true revelation of God’s will for all men. To deny it is not to honor the Word, or its Author but to dishonor it and therefore Him.