There exists only one universal moral law of sentient beings: Reciprocity. And it has been written since the dawn of writing in both via-positiva form as the golden rule, and in via-negativa form as the silver rule.
Via-Negativa: Do not unto others what you would not have them do unto you.
Via-Positiva: Do unto others as you would have them do unto you.
The one law of Reciprocity that we call Natural Law, is this:
“The only moral actions are those that consist exclusively of productive, fully informed, warranteed, voluntary transfer, free of imposition of costs upon the investments of others by externality.”
So all displays, words, and deeds that are not immoral, are either amoral (not immoral) or moral (productive).
But We Are Frequently Immoral
Unfortunately, while the via-negativa version is more accurate and less open to misinterpretation, the via-positiva is more popular for the simple reason that it is more open to intentional misinterpretation – as a POSITIVE demand for behavior rather than a NEGATIVE demand that we eschew behavior.
And men and women are natural deceivers in pursuit of discounts on their acquisitions. So we see people claim that it is moral to impose costs upon others. We see this false claim in (a) demand for sacrifice rather than limiting demand to non-imposition upon others. (b) demand for positive freedoms that impose costs upon others, rather than negative freedoms that prevent us from imposing costs upon others. (c) demand for ‘human rights’ the last few of which impose costs upon others, rather than Natural Rights, which demand we impose no costs upon others.
And via negativa prohibition on imposition of costs, is something all can do, while demand for the imposition of costs upon others is not something we can all do, nor can we pay such demands, nor is it clear that by paying such demand we do other than increase the immorality of such demands.
So the one universal moral law of sentient beings is the via negativa form of do not unto others as you would not have them do unto you, and the via positiva form is open to use by fraudulent pretense.
The Seen and Unseen
Now, enter the seen and unseen: It turns out that the optimum group strategy for any and every polity, is to exhaust opportunity for cooperation as a cost of converting immoral people into moral people – but only on an interpersonal, not political basis. So if we use government charity or professional charities we simply increase immoral behavior in the government, in the charity, and in the polity – because subsidy of immorality always serves to increase immorality (the chief means of immorality is reproduction of children one cannot afford, and entrapping others in the moral hazard of supporting your children, rather than additional children of their own.)
Christian Forgiveness and The Natural Law of Torts
This is the economic strategy of via-positiva Christian forgiveness, and via-negativa of Aristocratic (Militia) Law of Tort. The vast crimes of the three Abrahamic religions (Judaism, Christianity, and especially Islam) in creating the Abrahamic Dark Age and the destruction of the great ancient civilizations, aside, the economic reality is that interpersonal responsibility for the conversion of others from immoral to moral actors, and resorting to legal (communal) prosecution when it fails, is the reason for Christianity’s spread of wealth wherever it goes.
While western man evolved individual Sovereignty, the Jury, Thang, and Senate, the independent Empirical Judiciary, the independent common law of torts, using the natural law of reciprocity, that strategy is maximized, by the same personal responsibility for one’s behavior, the domestication of one’s children, domesticating the underclasses, and domesticating the foreigners lacking long traditions in individual Sovereignty, Individual responsibility, Natural Law by Exhaustive Forgiveness but not exhaustive tolerance. And then resorting to the commons to punish those who cannot adapt to that moral standard.