Milton expands less than three chapters of Genesis into over 12,000 lines of blank verse. This expansion presents him with a variety of artistic challenges and choices.
The Problem of Representing Paradise...
and the state of innocence when the poet is himself a product of the Fall and has only fallen, slippery, unreliable language at his command.
How does one communicate what the paradisal condition is LIKE when no one reading your poem has ever experienced or seen anything remotely LIKE the thing you are talking about? (How, for example, do you represent Edenic sex? See IV.763ff.)
For more on the Miltonic deployment of epic simile in Hell and Paradise, see handout on invocations of likeness and unlikeness.
Fallen language is always potentially double-edged. Consider, for example, the lingering implicit comparison (in the "fair field of Enna" passage) between Proserpina/Eve.
Retrospective Causality and the Characterization of Eve
Does Milton, knowing that in the Genesis narrative Eve eats the apple first, write back that knowledge into his account of the unfallen state, suggesting WHY it is that the serpent approached her first?
The Double Presentation of Adam and Eve (IV.288ff)
Note Milton's inability to imagine perfection in terms that dispense with the familiar and historically contingent sexual hierarchy which privileges "male" strength (physical & intellectual) over "female" beauty & softness?
Satan's Response to Adam and Eve (IV.502ff)
Note in particular 505ff--hell as a state of unfulfilled desire
521ff: "building ruin." Satan as miscreator again.