Hail holy light, offspring of Heav'n first-born,
Or of th'eternal Coeternal beam
May I express thee unblam'd? since God is light,
And never but in unapproached light
Dwelt from Eternity, dwelt then in thee,
Bright effluence of bright essence increate.
Or hear'st thou rather pure Ethereal stream,
Whose Fountain who shall tell? before the Sun,
Before the Heavens thou wert, and at the voice
Of God, as with a Mantle didst invest
The rising world of waters dark and deep,
Won from the void and formless infinite.
Thee I re-visit now with bolder wing,
Escap't the Stygian Pool, though long detain'd
In that obscure sojourn, while in my flight
Through utter and through middle darkness borne
With other notes than to th'Orphean Lyre
I sung of Chaos and Eternal Night,
Taught by the Heav'nly Muse to venture down
The dark descent, and up to reascend,
Though hard and rare: thee I revisit safe,
And feel thy sovran vital Lamp; but thou
Revisit'st not these eyes, that roll in vain
To find thy piercing ray, and find no dawn;
So thick a drop serene hath quencht their Orbs,
Or dim suffusion veiled.
John Milton, Paradise Lost, Book III, ll 1-26
In classic epic style, Paradise Lost opens in media res, so that after the general opening (the statement of purpose and the invocation of the muse: again, all in classic style) we find ourselves in Hell with the fallen angels. After two books in which we see Satan gather his forces and plot his revenge, the third book brings us up to Heaven at last (three: a mystic number, the number of the Trinity). The book begins with a rhapsodic invocation of light that immediately turns into a probing series of questions about its essential nature: God's first manifestation ("offspring of Heav'n first-born")? Or actually equivalent to God ("of th'eternal Coeternal beam")? Or possibly, referring back to the division of the waters above and below Heaven on the second day of Creation (Genesis 1, 6-8), light is some sort of ethereal liquid ("pure Ethereal stream"), though again Milton raises the question about the ultimate source and identity of light: "whose Fountain who shall tell?" Just as we consider light both wave and particle, Milton finds this primal substance to be of simultaneous multiple natures (making it an apt symbol for the Trinitarian God). It is typical of Milton that rhapsodic praise is not only not separate from probing intellectual inquiry, they are consubstantial; he has no use for unexamined faith.
There is a constant dialogue in Milton's poem between the great classical epics and myths and what he saw as the manifestation of truth in Christian revelation. Although Orpheus in classical legend descended to the Underworld, Milton cannot copy "th"Orphean Lyre" for his own descent into the grimness (and to some extent the grandeur) of the true Hell, bordered by Chaos, a place of Eternal Night, so he considers and rejects Orpheus as a model. As the poet begins the difficult task of describing the heavenly ineffable to his fallible and fallen readers (how much easier to help us appreciate Hell!), he again invokes the Muse, but the Heavenly Muse of divine (Biblical) inspiration, rather than the classical Muses. This passage ends with a reference to the poet's blindness; he goes on, in the lines after these, to compare his situation to that of the blind poets and seers of ancient Greece.
This reference to his blindness and the suffering it causes him (" . . . but not to me returns / Day, or the sweet approach of Ev'n or Morn, / Or sight of vernal bloom, or Summer's Rose, / Or flocks, or herds, or human face divine; / But cloud instead, and ever-during Dark. . . ") is not only a personal lamentation; it connects to the very basic purpose of his poem, which is to "justify the ways of God to men" (Book I, line 26). Milton's flexible syntax implies both that he will justify to men the ways of God, and also that he will justify the ways of God to men, that is, how God treats us: what did Milton do that warranted the affliction of blindness? Did he not go blind defending liberty (in the shape of Cromwell's Commonwealth) against a suspiciously Catholic-friendly Stuart king? It's also typical of Milton that he feels God not only can but needs to be justified to humanity.
Milton has much that is still of interest to say about theology and politics, but I wonder how many still read him for those reasons? No doubt they are outnumbered by those who read him for the poetry, which is endlessly astonishing and powerful. It's amazing that anyone, much less a blind man of limited means living (after the restoration of the monarchy) under state suspicion as a dangerous subversive, could compose a work of such sustained magnificence, sublime in its intellectual and aesthetic achievement. There was recent talk of a Hollywood 3-D version of Paradise Lost, starring Bradley Cooper as Satan, which is such a deliriously stupid idea I was planning to overcome my aversion to movie theaters and see it on its opening weekend. I assume the film-makers were attracted by the special-effects potential of the battle in Heaven (Book VI), but lines like "in his right hand / grasping ten thousand thunders" depend for their power on the reader's imagination and ear; if you turn that into a cinematic spectacular, all you're really doing is cranking the Dolby up to 11, which is ridiculous. Alas! the project was abandoned for lack of funds. Read over lines like "the rising world of waters dark and deep / Won from the void and formless infinite" and you know how seductive Milton can be, regardless of what you share or don't share of his beliefs. Yet the lines don't just sound good – they convey very specific details connecting the description to the religious and scientific beliefs of his time.
"Increate" in line 6 means uncreated; and in the next line, "Or hear'st thou rather" means "would you rather hear yourself called."
There are many editions of Paradise Lost; the one I usually carry around is the Signet Classic, edited and with notes by Christopher Ricks. I see the edition has changed its cover again. I'm on my third copy.