The best way to begin this is to look at what Apess did in A Looking Glass for the White Man. Apess repeatedly took Gospel readings and used them as a cudgel to bludgeon Whites. The holier-than-thou attitude was successful because he repeatedly contrasted those passages with his accusations against the Whites. When we compare this approach to Equiano, we find a similar result.
Equiano’s allusions had three effects. The first is that it showed blacks could engage with the higher European literature. The second effect is that it shows the slaves could relate to these works on a far more personal, physical level than most Europeans. The example I use below is a sterling example of this. This follows into the final effect, which is its appeal to Enlightenment individualism. In the mind of a historical European, what better proof could there be of individualist values than this black guy quoting the literature of the time? It would show that an African was capable of transcending the limitations of his race and using his intellect to become a fellow individualist. This sort of thing thrills contemporary adherents of individualism today; I doubt yesterday was any exception.
On page 103, at the end of Volume 1 and Chapter 5, Equiano quotes a passage from Paradise Lost. For context of the poem, the devils are debating what should be the next course of action, given that they’ve been ejected from Heaven. For the context of Equiano’s book, he is describing the torture inflicted upon his fellow slaves, and asking if not the owners feared any sort of violent retribution.
———–[No peace is given]
To us enslav’d, but custody severe,
And stripes, and arbitrary punishment
Inflicted? and what peace can we return,
But to our power hostility and hate,
Untam’d reluctance, and revenge though slow,
Yet ever plotting how the Conqueror least
May reap his conquest, and may least rejoyce
In doing what we most in suffering feel?
The correlation between these two accounts is obvious, and Equiano’s follow-up to this only goes to further solidify the effects listed above. Although he took it a little out of context (in the poem, the devil speaking decides to attack Earth and humanity instead of Heaven), the effect is still strong, in that constant repression results in restlessness – a message fit for the subject matter at hand.
But by changing your conduct, and treating your slaves as men, every cause of fear would be banished. They would be faithful, honest, intelligent and vigorous; and peace, prosperity, and happiness, would attend to you.
And that final word serves as a way to close off the story. Thus, all three effects listed above are fulfilled. It shows some slaves could read, it shows that the same slaves can relate to the work on a deeper level than the cozy Europeans, and it shows that the system of slavery was limiting blacks, preventing them from achieving their utmost individual potential.