'Twas mercy brought me from my Pagan landTaught my benighted soul to understand (1-2)
Wheatley doesn't come out and mention race at the beginning of the poem, but she does refer to Africa as "Pagan." That's probably because she didn't convert to Christianity until she moved to America. But a tension is set up here between Africa and America. It's almost as if Africa is bad, Pagan, and black, while America is good, Christian, and white. This is the dichotomy (two opposed groups) that she creates, which will later morph into a division between blacks and whites. Think of a coin: there are two exclusive sides, but they're part of the same coin, right? Blacks and whites were exclusive groups, but they're both human, and that's ultimately what Wheatley is trying to say.
Oh yeah, one last thing: "benighted soul" is an image that literally makes the speaker "dark." So, it could be figurative, like, untouched by the light of grace, but it could also be a literal darkness, as in a black, African, Pagan soul. This duality in language (literal and figurative) embodies the paradox of Wheatley's poem. Sometimes it sounds like she's putting her race down, saying that being black or dark is bad. And sometimes, those images of darkness are meant to be read as a religious, moral, and spiritual darkness. So, which is it? Has she been converted to a "white" way of thinking, or is she using figurative language to say two things at once? We can't say for sure, but it's clear that race complicates the speaker's identity.
Some view our sable race with scornful eye (5)
Wheatley went all out with the poetry flair in this line. Check out "sable race." But what's really cool is that word "sable." It means to be dressed in black, and it takes on a double-secret meaning. Well, not so secret, but it can be read two ways: (1) It can be interpreted as a darkness that is bad and unholy—an extension of the Pagan land where slaves were coming from in Wheatley's time, or (2) It can be interpreted as the literal darkness of the speaker's skin—and the skin of other slaves in America—but doesn't necessarily have a negative connotation. In fact, sable furs (sables are also mammals whose pelts were sold) were valuable. So, we could argue that she referred to "our sable race" as something precious and valued.
In other words, it's kind of hard to say. Or rather, Wheatley left the meaning ambiguous so her line can be interpreted several different ways. The doubling is fantastic, because it complicates the meaning of the poem and shows us conflicting point of view about race in her time.
"Their color is a diabolic die." (6)
Does the speaker mean evil dice? Like bad luck at the craps table? No, probably not, but she could mean "diabolic dye," as in an evil stain. She's talking about her black skin color and how it was viewed as evil back in the eighteenth-century day. In fact, this line is in quotes, so she's putting this line in the mouths of, we think, a white speaker. She's not saying that all white people felt this way. She's saying that "some" people viewed black Americans this way. So yes, race is front and center here, and something Wheatley addresses head-on.