Maybe another classical epic reference. Aristotle was talking about the august, heroic and godlike properties of the epic. Milton here wishes to "justify the ways of God to men", not just to make men in awe, but to make men understand what is heroic. By doing this, he deviates from the epic norm, and rebels (being the key word of the poem perhaps). "What in me is dark illumin" could be interpreted as a quest for knowledge, which led to the original sin. Do desire for knowledge and disobedience go hand in hand? And is disobedience so bad?

revolt, opposed, rebellious...words that reflect the act of disobedience and that keep coming up. Milton questions disobedience as an act of sin, and this is what I really like about the poem. It challenges the christian ideals of obedience.

The first reference to Satan clearly emerging as the hero of the poem.

Instead of praising heroic deeds to the likes of Achilles, Milton uses the formula to reflect upon the act of disobedience as a heroic act.

Clearly the opening lines of an epic, but varying greatly from the classical theme. Man's first disobedience seems to be the heroic deed the poem wishes to illustrate