640 lines. Raphael tells the story of Creation, mostly drawing on Genesis 1 but also bringing in some elements of Genesis 2 with regard to the creation of humans.

Milton invokes a Muse again, this time Urania (lines 1–39).
Adam and Eve listened to Raphael’s account of war in heaven, and now Adam wants to know about the creation of this world (lines 40–69).
Adam speaks (lines 70–108), asking Raphael to narrate creation.
Raphael speaks for the rest of the book (lines 110–640), describing the week of creation. But first he warns Adam not to seek knowledge beyond limit (lines 120–30).
Raphael’s account of creation picks up immediately after the war in heaven, and here we get confirmation on Satan’s prior name in heaven.
Know then, that after Lucifer from heaven
lines 131–36
(So call him, brighter once amidst the host
Of angels, than that star the stars among)
Fell with his flaming legions through the deep
Into his place, and the great Son returned
Victorious with his saints…
The Father addresses the Son (lines 139–73) who says that he will create a race of people in a new world in order to repopulate heaven after the loss of the rebel angels. These people will dwell on a new world.
there to dwell,
lines 156–61
Not here, till by degrees of merit raised
They open to themselves at length the way
Up hither, under long obedience tried,
And earth be changed to heaven, and heaven to earth,
One kingdom, joy and union without end.
He sends forth his Son and Spirit to create.
Raphael makes clear again that he’s adapting divine things to human comprehension (lines 174–79). The angels rejoice in God’s purpose (lines 180–91). The Son emerges from heaven and views Chaos (lines 192–215).
On heavenly ground they stood, and from the shore
lines 210–15
They viewed the vast immeasurable abyss
Outrageous as a sea, dark, wasteful, wild,
Up from the bottom turned by furious winds
And surging waves, as mountains to assault
Heaven’s height, and with the centre mix the pole.
The Son silenced the discord (lines 216–17).
The Son took the golden compasses to circumscribe the new world (lines 218–29).
The Son speaks (lines 230–31) = Gen 1:1–2, the creation of heaven and earth, “Matter unformed and void” (line 233). Raphael describes this primordial heaven and earth (lines 232–42)
Day 1 (lines 243–60), the creation of light, which came from “her native east” (line 245) though not from the as-yet-uncreated sun, so light was “Sphered in a radiant cloud” (line 247). The angels celebrate.
Day 2 (lines 261–75), the creation of the firmament, “expanse of liquid, pure, / Transparent, element air” (lines 264–65).
Day 3 (lines 276–338), the gathering of the waters, the appearance of dry land, and the sprouting of plants.
Day 4 (lines 339–86), creation of sun and moon and stars.
Day 5 (lines 387–448), fish and birds.
Day 6 (lines 449–580), creation of land animals (449–504), and then God turns his attention to his “masterwork” (lines 505–18).
The Father speaks (lines 519–23), pretty much equivalent to Gen 1:26.
He creates humans (lines 524–47), and the Son returns to heaven (lines 548–80).
Day 7 (lines 581–640).
The angels sang a song praising God (lines 601–32).
Raphael asks Adam if he has any more questions (lines 633–40).