Criteria to determine if a divine law really is from God
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How can it be known that an allegedly divine law really is from God?
Divine positive laws (for natural laws, being eternal and universal, are all divine) are those which, being the commandments of God, not from all eternity, nor universally addressed to all men, but only to a certain people or to certain persons, are declared for such by those whom God hath authorized to declare them. But this authority of man to declare what be these positive of God, how can it be known? God may command a man, by a supernatural way, to deliver laws to other men. But because it is of the essence of law that he who is to be obliged be assured of the authority of him that declareth it, which we cannot naturally take notice to be from God, how can a man without supernatural revelations be assured of the revelation received by the declarer? And how can he be bound to obey bound to obey them?...
Hobbes, Lev XXVI 40
It cannot be known "by natural reason" that a person really represents God (and thus can articulate divine law).
For the first question, how a man can be assured of the revelation of another without a revelation particularly to himself, it is evidently impossible: for though a man may be induced to believe such revelation, from the miracles they see him do, or from seeing the extraordinary sanctity of his life, or from seeing the extraordinary wisdom, or extraordinary felicity of his actions, all which are marks of God's extraordinary favour; yet they are not assured evidences of special revelation. Miracles are marvellous works; but that which is marvellous to one may not be so to another. Sanctity may be feigned; and the visible felicities of this world are most often the work of God by natural and ordinary causes. And therefore no man can infallibly know by natural reason that another has had a supernatural revelation of God's will but only a belief; every one, as the signs thereof shall appear greater or lesser, a firmer or a weaker belief.
Hobbes, Lev XXVI 40
Extended Argument We are bound by our own faith to obey the laws that are considered divine by the (laws of the) State.
But for the second, how he can be bound to obey them, it is not so hard. For if the law declared be not against the law of nature, which is undoubtedly God's law, and he undertake to obey it, he is bound by his own act; bound I say to obey it, but not bound to believe it: for men's belief, and interior cogitations, are not subject to the commands, but only to the operation of God, ordinary or extraordinary. Faith of supernatural law is not a fulfilling, but only an assenting to the same; and not a duty that we exhibit to God, but a gift which God freely giveth to whom He pleaseth; as also unbelief is not a breach of any of His laws, but a rejection of them all, except the laws natural. But this that I say will be made yet clearer by, the examples and testimonies concerning this point in Holy Scripture. The covenant God made with Abraham in a supernatural manner was thus, "This is the covenant which thou shalt observe between me and thee and thy seed after thee." [Genesis, 17. 10] Abraham's seed had not this revelation, nor were yet in being; yet they are a party to the covenant, and bound to obey what Abraham should declare to them for God's law; which they could not be but in virtue of the obedience they owed to their parents, who (if they be subject to no other earthly power, as here in the case of Abraham) have sovereign power over their children and servants. Again, where God saith to Abraham, "In thee shall all nations of the earth be blessed: for I know thou wilt command thy children and thy house after thee to keep the way of the Lord, and to observe righteousness and judgement," it is manifest the obedience of his family, who had no revelation, depended on their former obligation to obey their sovereign.
At Mount Sinai Moses only went up to God; the people were forbidden to approach on pain of death; yet were they bound to obey all that Moses declared to them for God's law. Upon what ground, but on this submission of their own, "Speak thou to us, and we will hear thee; but let not God speak to us, lest we die"?
By which two places it sufficiently appeareth that in a Commonwealth a subject that has no certain and assured revelation particularly to himself concerning the will of God is to obey for such the command of the Commonwealth: for if men were at liberty to take for God's commandments their own dreams and fancies, or the dreams and fancies of private men, scarce two men would agree upon what is God's commandment; and yet in respect of them every man would despise the commandments of the Commonwealth.
I conclude, therefore, that in all things not contrary to the moral law (that is to say, to the law of nature), all subjects are bound to obey that for divine law which is declared to be so by the laws of the Commonwealth. Which also is evident to any man's reason; for whatsoever is not against the law of nature may be made law in the name of them that have the sovereign power; there is no reason men should be the less obliged by it when it is propounded in the name of God. Besides, there is no place in the world where men are permitted to pretend other commandments of God than are declared for such by the Commonwealth. Christian states punish those that revolt from Christian religion; and all other states, those that set up any religion by them forbidden. For in whatsoever is not regulated by the Commonwealth, it is equity (which is the law of nature, and therefore an eternal law of God) that every man equally enjoy his liberty.
Hobbes, Lev XXVI 41