I’ve not looked at the thread for several days so apologies if this has been said before, but this sounds like a version of the Euthyphro dilemma - is an act morally good because God commands it, or does God command it because it is morally good?
*"as Plato emphasized in Euthyphro, one is also left with the difficulty of explaining why God’s commands are authoritative.
One plausible answer might be that God’s perfect knowledge of right and wrong, or God’s own moral perfection, explains why his commands serve legitimately as standards for us. But that answer assumes that standards of morality exist independently of God’s will (either as objects of his knowledge or as standards in light of which He counts as morally perfect), in which case speaking of morality as consisting of God’s commands will not explain the origin or nature of these independently existing standards.
Alternatively, one might eschew an appeal to God’s knowledge or goodness and claim that there is no independent standard for God’s will and nature. But that leaves in place the puzzle concerning the authority of moral principles. If we reject the idea that God’s commands reflect His knowledge of right and wrong, and reject as well the idea that God is all good, it seems reasonable to wonder why his commands have any special authority." -
plato.stanford.edu/entries/metaethics/#EutPro*
I think Aquinas rejected the dilemma but don’t know his argument.