In Wheatley's hymn, Humanity is not an abstract quality but a person, a young prince who walks out of his "azure-paved hall" in heaven and drops toward "this dark terrestrial ball." The first stanza plays with scale. Heaven gets a sky-blue floor, while the whole Earth shrinks to a dim sphere hanging in the dark. Even the syntax makes the descent. The opening lines are twisted so that the verb "Forsakes" arrives late, and the sentence tumbles down to the earth in the same way its subject does.
What follows is a small myth. The "sire of gods and men" presses his son to his breast and sends him off with a job. Humanity must "succour man's afflicted son," and he does it by working on the mind: "Enlarge the close contracted mind, / And fill it with thy fire." The mind here is a cramped room, and Humanity is both the one who knocks the walls out ("bounties unconfin'd") and the fire that fills the new space. Kindness, in this picture, is not something people simply have. It has to be inspired into them from outside, and that gives the poem a quietly pointed edge.
The form carries the hymn-like feeling. Each six-line stanza rhymes aabccb, and the lines alternate between longer eight-syllable lines and short six-syllable ones. The short third and sixth lines land like a bell. "A prince of heav'nly birth!" opens the poem, and "At his descent to earth!" closes the stanza, so that *birth* and *earth* mark heaven and ground at either end. The meter can also hurry. "He wings his course from star to star" is almost all single syllables, and the god seems to step across the sky one star at a time.
The poem turns in stanzas IV and V, when the myth narrows to a single room. "Their G——! then thy raptur'd heart / Perceiv'd the rushing God." The blank hides a name or word, and from here the poem speaks to a "thou," a friend whose heart has felt Humanity arrive. Wheatley then puts herself into the picture, and with deliberate modesty. Her muse is "languid" and "in low degree," and it is the friend's "pitying eye" that sees it. At that friend's "desire," the nine Muses descend. Her own part is hedged with "methought" and a doubled "deign'd," as if she cannot quite believe the honor. The poem sets out a chain of gifts, running from heaven to the friend to the poet's lyre. Humanity is shown at work in the very act of helping her write.
The last stanza puts a question to the reader: "Can Afric's muse forgetful prove?" It works as a thank-you, since gratitude is the answer the question expects, but it also does something else. Greek-style Muses, Graces and a "laurel-crown'd" Friendship fill the stanza, and in the middle of them Wheatley names her own muse by a continent. She uses the classical machinery of polite eighteenth-century verse, and she signs her place in it with where she comes from.
That is where the poem's significance lies. Wheatley was an enslaved woman born in Africa, and given that, the repeated phrase "human heart" ("Each human heart inspire" in stanza III, "A tender human heart" in stanza VI) carries more than a stock compliment. The poem gives its Humanity a divine father and a heavenly mission, and it shows that quality being felt by a "tender human heart" and returned by an African poet. The poem never states an argument, but its logic is clear enough. If Humanity is a god sent to enlarge narrow minds, then the poet who answers with grateful verse stands inside the circle of the human, not outside it. The conventions are polished and a little formal, but under them the poem makes a claim about who gets counted as human and who gets to sing about it.