Is this morally acceptable?

If you happen to be a Christian living during the time of antichrist rule and you can't buy or sell because you did not take the mark, would it be morally acceptable to steal and kill to get what you need during that time, such as food? If the rest of the world is operating under a satanic system, why would Christians be obligated to show any morals toward that system? Wouldn't it be morally justified to steal from and kill agents of Satan?