Is man's law always right? It can't be for a lot of reasons, one of them being that the laws of man constantly evolve and devolve, additionally man by definition is changing and fallible. If, however, you believe that man's law is absolutely right, and should always be obeyed in any and all circumstances, than the crucifixion of our Lord on the flimsy evidence of Christ proclaiming himself a King and therefore in rebellion against Rome, in which Christ consequently suffered the penalty of this crime, which was death by crucifixion, then you would approve and commend his crucifixion. That is man's law, not God's, and of the countless injustices here on earth, can we think of any less justified than the crucifixion of Christ.
I submit to you that man's law is ever changing and not always right, making it problematic and questionable to obey all laws, just because it is a law. No doubt, this then does present a problem in regards to which law man must answer to. You must as a matter of course, always answer to the Highest Law which is God's Moral law; doing so, however, will potentially bring you into conflict with man's law and therein lies a problem not easily resolved.
No man, given free will, must obey God's law or man's law for that matter, but failure to do so, will have consequences. Obeying all of man's law is difficult because even the finest lawyers in the country don't know all the laws, or their application, or their history, or their contradictions, meaning that you as a citizen can at best, presume that you are obedient to all laws but that is merely a presumption. But what about Moral law; how can we find it, know it, and obey it? Moral law is something that is imprinted on our conscience. The precepts of Moral law are the same precepts of the great prophets and messiahs of history which have in common such attributes as: surrender (to God), sacrifice, diligence, fortitude, integrity, temperance, brotherhood, and love (of God and neighbor). Further to this point, Martin Luther King, Jr., in his Letter from a Birmingham Jail, stated: “Any law that uplifts human personality is just. Any law that degrades human personality is unjust.” … “One has not only a legal but a moral responsibility to obey just laws. Conversely one has a moral responsibility to disobey unjust laws.”
Man can has created many unjust and hateful laws and continues to do so until this day, because the history of man is so often the history of man's injustice and oppression of his fellow man. Man's laws are necessary and needed in order to enforce upon mankind, proper and corrected behavior, to heal wounds, to right injustices, to protect the defenseless, to assure fair play, and as a touchstone for society at large.
True justice can only come from correct and constant application of True Law. Man's law must be in accordance with Moral law, those laws that are not in harmony, are laws onto themselves and therefore are false laws with foundations of sand and untruth.