Now, if you want an answer to what you describe as the modern terms, it is that something is moral because god commands it. God’s game, god’s rules.
Today, it is really the progressive activist who is closest to the essential truth of all political endeavor - the fact that Might makes Right.
One thing I remember having pounded into my head as a child is that “might does not make right.” I was told this because, as the oldest, strongest, and tallest of my brothers, I had a tendency to use my physical dominance to get them to do what I wanted. Of course, the assertion that “might does not make right” was obviously false. Clearly I was getting my way by using power. It was not, however, until I saw both Vox’s and Moldbug’s posts that I finally figured out how to correct the assertion: Might does indeed make right; however, you’re not the mightiest person.
God, of course, is the mightiest being, and it is entirely his choice to give power to whomever he chooses, for whatever reason he chooses. If he chooses to give power to the Prince of the Power of the Air, he can certainly do so. If God chooses to give power to certain nations and states, or to certain people, it is certainly his prerogative.
Furthermore, anyone to whom God gives power generally has the authority to delegate their authority to others (of course, there are obvious limits to this). Also, since all spiritual and human beings have free will, there is no reason to believe that anyone is compelled to use their power responsibly. As such, God could delegate power to certain beings in good faith only to have those beings abuse their power (this would certainly have been the case with Satan, and appears to have been the case with King Saul, as well as others).
The salient point, though, is that all men must give an account for what they have done. If God gives you power and authority and you misuse it, you will answer to God for doing so. God may not subvert your freedom of choice in order to make you use your power responsibly, but that doesn’t mean that your choices are consequence free.
Thus, a more helpful mindset is to acknowledge that, practically speaking, might does make right. In keeping with this, the being with the most might is the one who makes the ultimate standard of right. Therefore, it would be better to teach children to use might responsibly instead of asserting that “might does not make right,” for teaching generally good children to shun power instead of wielding it responsibly will only ensure that the corrupt will seek power and misuse it accordingly.