The narrator is a young black boy. He insists that though his exterior is black, inside his soul is as white (pure) as the angelic-looking English child. His mother taught him that this life is only a period of trial and preparation, in which he will learn to bear the 'beams of love' emanating from the sun where 'God does live'. In God's kingdom, however, he and the white boy will play around God's tent like innocent lambs. The black boy will become like the white boy, who in turn will learn to love his black counterpart.

This poem, composed in 1788, dates from the dawn of the anti-slavery movement, just a year after the Society for the Abolition of the Slave Trade had been founded. Its key feature is the power-shift between the black boy and the white boy that occurs in the course of the poem. In the first verse, the black boy feels physically inferior to his white counterpart. The English child is 'white as an angel', while the little black boy is pictured as a benighted heathen - 'black as if bereav'd of light'. But the black boy, following his mother's explanation of his skin-colour through to its conclusion, convinces himself that his dark skin actually has the positive effect of enabling him to get closer to the 'light' and 'heat' of God's love. Once in God's kingdom, he, the black boy (who can stand unsupported), will actually be stronger than the white boy (who will have to 'lean...upon our father's knee'.). Nonetheless the black boy will not take advantage of his superiority to show vengefulness, but will show compassion to the white boy by 'shading him from the heat' and 'stroking his silver hair'. Blake suggests that in God's kingdom colour is irrelevant. Both white and black skins are described as 'clouds' that interfere with the sun's rays (God's love), dulling our perception of the things all races have in common, most importantly, our shared humanity.