Analyses of Tennyson's famous poem invariably speak of the poet's use of masculine pronouns, and of the word "hands" to denote the bird's talons. The clauses "he stands" and "he falls," which conclude stanzas one and two respectively, contain verbs not usually associated with a bird. One would expect verbs like "perches" or "swoops" (if not the rich ambiguity of "stoops"). This is what is meant by personification.
Although line one is unvaried iambic tetrameter - four accents following unaccented syllables - lines two and three begin with a variation. The accented "Close" is followed by the unaccented syllable "to"; then the iambic rhythm returns with "the sun in lonely lands. This variation (called a trochaic substitution) is repeated in line three: "Ringed with the azure world he stands."
The opening three-line stanza is a still picture. The reader views the motionless eagle from below. This lack of motion is reinforced by the alliteration of words beginning with the consonant combinations "cl" and "cr." There is assonance, or repeated interior vowel sounds, in "clasps," "crag," and "hands." The last three consonants of "clasps" do not roll easily from the tongue and reinforce the idea of rigid immobility. As always in great poetry, sound reinforces sense.
In those opening lines we are looking upward at the bird, whose name symbolizes nobility and keen vision. In the concluding three lines we are on the same elevation as the bird and are looking downward at the "wrinkled sea," the movement of which from our vantage point is reduced to a "crawl." We are "ringed with the azure world," the ring being the encircling horizon.
Tennyson is using his eagle as a personification of the archetypal tragic hero. The use of "He" and "hands" humanizes the bird. "Close to the sun" resonates with the Icarus/Daedalus myth. Daedalus was the master craftsman who escaped from the labyrinth on Crete along with his son Icarus. The two escaped by flying on the wax and feather wings made by Daedalus. Icarus flew too "close to the sun," and his wings melted causing him to fall to his death.
"Lonely lands" recalls Aristotle's definition of the tragic hero who acts alone and suffers for his prideful defiance of the gods. The "mountain walls" may echo the myth of Prometheus, the hero who rebelled against the gods and for his punishment was chained to mountain walls.
The stasis of stanza one gives way to movement first with the word "crawls" in stanza two. We join the eagle and look down through the bird's eyes. From this elevation, huge ocean swells seem distant, slow-moving wrinkles. Then the swift-moving labials of "like a thunderbolt" are appropriate to the stoop (or predatory swoop) of a bird of prey as well as a reminder of classic myths such as Zeus, the deliverer of thunderbolts.
"He falls" is the heroic defeat of the mythic hero, of the one who flew too close to the sun, who all alone wrested fire from the gods.
English teachers value this seemingly simple poem. It provides them with clear demonstrations of personification, metrical variation or substitution, alliteration, and allusion, and the way that these devices interact to generate extra meaning.