Worshipping Caesar would be immoral. However, not registering a gun if Caesar demanded it? That’s not so morally clear cut to me as Christian.
BTW, I’m only expressing my own thoughts on the matter and not advocating for or against any other position. I’m simply saying it (gun registration or confiscation) would not be a simple issue, clear cut issue for me. It would also be a deadly serious decision of course.
I don’t really see any spiritual issue here with not registering or turning them in.
The Scriptures tell us that we obey the laws when they do not directly conflict with Scripture itself (Rom. 13:1, Titus 3:1, I Pet. 2:13-14, etc.)
HOWEVER.
In our system, what is the highest earthly law? It is the Constitution. The Constitution is what it is- Not what the SCOTUS says it is, for the Constitution itself nowhere gives SCOTUS any prerogative to interpretively overturn its provisions, or even to engage in any kind of “judicial review.”
Ergo, whenever any act of government goes contrary to the Constitution (which we the people are to decide through our states, since that was the scenario for ratification), it is null and void.
No SCOTUS decision that “interprets” the 2nd amendment as a collective right only has any standing. No federal law which seeks to restrict or overturn, in practice if not in word, the right to keep in bear arms has any standing.
If the Christian wants to obey the law, then they first and foremost obey the Constitution. All other powers are subsidiary to it, are instituted by it, and therefore have no legal standing to overrule it.
Obeying the Constitution, in our system, is fulfilling Rom. 13:1, etc. We obey it - not any subsidiary power which conflicts with it.