Everything that is made comes with a set of instructions. Whether it is home appliances, toys, automobiles, pet accessories, clothing, food, etc.
Food and clothing don't come with instructions for many people. They have to grow and cook their food as they see fit. Clothing likewise has to be grown and made. The essentials of life come with no instructions, need no instructions, if lore and habit passed on from generation to generation is followed.
There are people today who have no Bibles, no part of a Bible, and could not read them if they had them. But they have heard the gospel, by word of mouth, and they have the Holy Spirit, who guides them. They would do better with a Bible, preferably not a translation, but they are certainly better off than a person with a Bible but without the Holy Spirit, of which there are very many.
There was secular law a long time before the Decalogue, expressing natural law against murder, theft, adultery and false witness. There was law in favor of idols and their worship, and arguably, there still is. There can be no law against coveting, and using the Lord's name in vain is very hard to legislate against. There is no natural sabbath law, and very few if any states that attempt to implement one today. If they make any serious attempt to do so, they have to legislate against lighting fires, or using electricity, on their designated sabbaths.If you really look close, you will see that all of man's laws have the Ten Commandments as their foundation.
Mankind has a natural regulator called the conscience, allied to common sense, and all good law is based upon that.
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