How we cite our quotes: Book Number, Line Number
Quote #1
"Him haply slumb'ring on the Norway foam
The pilot of some small night-foundered skiff,
Deeming some island, oft, as seamen tell,
With fixèd anchor in his scaly rind
Moors by his side, under the lee" (1.203-7)
Milton compares Satan to a giant creature that some "pilot" might mistake ("deeming some island") for an island; the point of the simile is that Satan seems like one thing (a heroic leader, an unjustly maligned angel), but is really another. In other words, he's a gigantic symbol of deception.
Quote #2
"he seemed
For dignity composed and high exploit:
But all was false and hollow" (2.110-12)
Milton here describes Belial; notice the rhetoric of "seeming." It is implied in the famous simile about the island (described above), and discussed more explicitly here. Belial is "false and hollow," a description that resonates nicely with the canon sequence (described below). Things are not always what they seem in this poem; in fact, they are often not what they "seem."
Quote #3
"Whereof he soon aware,
Each perturbation smoothed with outward calme,
Artificer of fraud" (4.119-21)
All of Satan's emotions are normally visible on his face, but here he shows his ability to display an "outward calm," even though he's as far from calm as one could get. The rhetoric of artificiality is quite patent here; we see it not only in "smoothed over," but also in "artificer." The latter contains the word "art" in it, suggesting that Satan is also some type of bad artist or something, or at least one that is more focused on the inauthentic than the natural.