Randy Rosenthal is co-founding editor of the literary journals The Coffin Factory and Tweed’s Magazine of Literature & Art. He studies religion and literature at Harvard Divinity School.

In “God: A Biography,” Jack Miles wrote about the life of God as the protagonist of a classic of world literature: the Hebrew Bible. It was a brilliant approach, because the one thing we know for sure about God is that he exists as a literary character. Miles took a similar tack in “Christ: A Crisis in the Life of God,” considering the New Testament as if it were a stained-glass window to be “looked at and appreciated as a work of art, rather than seen through in an attempt to discern the historical events that lie behind it.” Now he’s completed a sort of trilogy with “God in the Qur’an.” Yet this third book, which could have simply been called “Allah,” is much more modest than the other two, in both content and ambition.

For starters, there is the length. “God: A Biography” is more than 450 pages, while “God in the Qur’an” is just under 250, and Miles references the Bible in it as much as he does the Koran. It’s clear where his expertise lies; he admits he doesn’t know Arabic. (This discrepancy could also simply reflect the fact that the Bible, an anthology created by many authors over a period of 1,000 years, is five times longer the Koran.)

Despite being an Episcopalian, Miles says he writes not as a religious believer but as a literary critic, and so he approaches the Koran as he does the Bible. That is, he looks at scripture “not through belief but through a suspension of disbelief.” He accepts scripture “on its own terms,” just as we do when reading a novel or watching an art film. And with this key, Miles avoids the distracting question of belief, thereby enabling us to understand.

But rather than being a thorough excavation of Allah, “God in the Qur’an” focuses on the sections of the Koran that retell biblical stories. The Koran is, after all, Allah’s revision of biblical scripture, a correction, and Miles looks at these differences to see what Allah reveals about himself — and how he is different from Yahweh-Elohim. As Miles writes, “It isn’t the devil, in this case, that is in the details but the deity.”

Starting with the story of Adam and Eve, Miles teases out omissions and additions in the Koranic version that highlight doctrinal differences but also show that, in a sense, the Koran has more in common with Milton’s “Paradise Lost” and Dante’s “Inferno” than the Bible. For instance, the Genesis story makes no mention of Satan or an afterlife, though these are emphasized in the Koranic version of the fall. Yet the major difference is that in the Koran, man is not made in God’s image, implying there is no familial relationship between God and man. As Miles writes, “Allah is just not like that.”

Moving on to Cain and Abel, it’s clear that whereas the Genesis story is about an event, the Koran version is a moral tale. Unlike Yahweh, Allah has nothing to do with Abel’s murder, and he is more merciful to Cain. Whereas Yahweh is portrayed as figuring things out as he goes along, often being surprised, confused and angered by his creation’s behavior, Allah is “more decisive, more certain in advance of the universal and permanent significance of all that He says and does.”

Nowhere is this clearer than in the story of Noah. In the Koran, Noah is a prophet, like Jeremiah. He warns his fellows about the coming flood and tells them that those who surrender — i.e. become Muslims — will be saved. In the Bible, there’s no warning from Noah, and so he is not a prophet. This insertion is significant, because in revising the portrayal of himself, Allah comes off as much less unpredictable and emotionally reactive than Yahweh. Ferociously severe, yes. Recklessly volatile, no.

In the Bible, Yahweh often acts like a violent, jealous lover. Yet Allah is like a stern but forgiving grandfather. That is, the God of the Koran is much closer to the image we commonly conjure as God. Miles goes on to analyze the parallel stories of Abraham, the binding of Isaac, Moses and Jesus, but the overall effect is the same: In his revisions, Allah presents himself as truly omniscient, all-wise and merciful.

Aside from theological differences, it’s interesting to note that from a literary perspective, the revised stories in the Koran are told with less indirection than they are in the Bible. The Koran fills in the gaps, as it were. But it is those very gaps that make the Hebrew Bible so intriguing — the unanswered whys give the Bible its ambiguity, irony and suspense. And in his retellings, Allah constantly cuts off tension before it has a chance to build up. Allah is determined to deliberately “spoil” or “give away” the story, as Miles writes. “In Allah’s way of retelling a Bible story for Muhammad’s benefit, the moral of any story permeates it from the beginning. Entertainment merely distracts from that moral point.” And so with its corrections, the Koran loses the literary artistry of its predecessor.

But of course, the Koran is to be recited, and, as Miles notes, there is “a voice beyond the Arabic and beyond even Muhammad” that can’t be captured in translation or transcription. It may be true that the Koran is not nearly as artistically sophisticated as the Bible, but that’s beside the point, because it is ultimately a message that is meant to be heard, not necessarily read.

God in the Qur'an

By Jack Miles

Knopf. 241 pp. $26.95