What does Edgar Allan Poe mean by "supererogation is not presumable of any Divine Act"?

Question

I am reading Edgar Allan Poe's Eureka: A Prose Poem, "an essay on the material and spiritual universe". I have come across a sentence where I can't get what the author is trying to say. It seems impossible for me to sort out the syntax. Here is the context, with the difficult sentence in bold:

Now, of these atoms, thus diffused, or upon diffusion, what conditions are we permitted—not to assume, but to infer, from consideration as well of their source as of the character of the design apparent in their diffusion? Unity being their source, and difference from Unity the character of the design manifested in their diffusion, we are warranted in supposing this character to be at least generally preserved throughout the design, and to form a portion of the design itself:—that is to say, we shall be warranted in conceiving continual differences at all points from the uniquity and simplicity of the origin. But, for these reasons, shall we be justified in imagining the atoms heterogeneous, dissimilar, unequal, and inequidistant? More explicitly—are we to consider no two atoms as, at their diffusion, of the same nature, or of the same form, or of the same size?—and, after fulfilment of their diffusion into Space, is absolute inequidistance, each from each, to be understood of all of them? In such arrangement, under such conditions, we most easily and immediately comprehend the subsequent most feasible carrying out to completion of any such design as that which I have suggested—the design of variety out of unity—diversity out of sameness—heterogeneity out of homogeneity—complexity out of simplicity—in a word, the utmost possible multiplicity of relation out of the emphatically irrelative One. Undoubtedly, therefore, we should be warranted in assuming all that has been mentioned, but for the reflection, first, that supererogation is not presumable of any Divine Act; and, secondly, that the object supposed in view, appears as feasible when some of the conditions in question are dispensed with, in the beginning, as when all are understood immediately to exist.

Answer 1

A paraphrase would be God doesn't do more than He needs to. To paraphrase more closely we cannot presume that any divine act would include anything unnecessary.

Supererogation means doing more than is asked of you or than is required; it generally refers to what is morally required, but can refer to what is legally required or other areas as well (as the link shows). Poe is usually considered as holding some form of monism (a belief that the universe is at bottom all one thing or all unified) and in the extract he appears to be arguing that God wouldn't create lots of different unrelated atoms but instead would create lots of atoms that are fundamentally the same, all derived from a basic unifying principle he refers to as the "One". (The fact that God is supposedly all-knowing would add weight to Poe's claim that God doesn't do anything unnecessary.)

But good luck understanding Eureka; academic opinion seems to differ on whether and to what extent it's serious or a joke.