David Hume on Divine injustice, with a surprising twist

"Were there a species of creatures, intermingled with men, which, though rational, were possessed of such inferior strength, both of body and mind, that they were incapable of all resistance, and could never, upon the highest provocation, make us feel the effects of their resentment; the necessary consequence, I think, is, that we should be bound, by the laws of humanity, to give gentle usage to these creatures, but should not, properly speaking, lie under any restraint of justice with regard to them, nor could they possess any right or property, exclusive of such arbitrary lords. Our intercourse with them could not be called society, which supposes a degree of equality; but absolute command on the one side, and servile obedience on the other. Whatever we covet, they must instantly resign: Our permission is the only tenure, by which they hold their possessions: Our compassion and kindness the only check, by which they curb our lawless will: And as no inconvenience ever results from the exercise of a power, so firmly established in nature, the restraints of justice and property, being totally useless, would never have place in so unequal a confederacy." (Enquiry Concerning the Principles of Morals, 3.1). This is one of the most disturbing passages in David Hume. (Kate Abramson and Steve Darwall brought it to my attention when I started working on Hume's moral theory, and I keep returning to it.) I offer five observations on it.

1. 1. It captures an important truth about the non-universal scope of justice, and I return to that below.
2. 2. It also reminds us of the significance of the virtue of humanity in Hume (about which Kate Abramson, Jacky Taylor [in the Cambridge Companion], Ryan Hanley, David Levy, Robert Shaver, and Remy Debes have written very insightfully).
3. 3. It offers evidence that according to Hume there are at least two normative frameworks -- one governed by considerations of justice and the other one governed by the laws of humanity [and associated with important virtues such as compassion and kindness] --, which are not identical. Moreover, it is unclear that either always must have authority over each other. (This is not to deny that according to Hume there may be circumstances in which one can have authority over the other, and he is certainly an advocate of humanity.) Again, there is more than an important kernel of truth here (recall my discussion here).
4. 4. It just dawned upon me that if there were a Christian god, then we humans would be in the position of the species of inferior creatures in our relationship toward the Deity. If so it follows from Hume's argument that we don't fall in the sphere of God's justice; we can only count on his compassion. Now, I am no Christian theologian, but I suspect this is a serious heresy (one that Priestley made almost explicit in his claim that justice is a modification of divine benevolence. [This made Priestley a target of much criticism as can be traced on Google.books.])
5. 5. Hume's position also undercuts a lot of arguments against Jewish-Christian Theism that center on, say, God's injustices (for a long list of such injustices, see here). According to Hume these arguments have no standing because we cannot make our resentment toward God felt. I don't recall this position being hinted at in Hume's Dialogues, which, I think, is further evidence that in that book nobody speaks for Hume.