And sitting down before the heat of day,
She took me on her lap and kissed me,
And pointing to the east began to say.
Look on the rising sun: there God does live
And gives his light, and gives his heat away.
And flowers and trees and beasts and men receive
Comfort in morning joy in the noonday.
And we are put on earth a little space,
That we may learn to bear the beams of love,
And these black bodies and this sun-burnt face
Is but a cloud, and like a shady grove.
For when our souls have learn'd the heat to bear
The cloud will vanish we shall hear his voice.
Saying: come out from the grove my love & care,
And round my golden tent like lambs rejoice.
Thus did my mother say and kissed me,
Earlier in the poem, the mother says to the child that his blackness is like a cloud. Here she tells him that if he learns to bear hardship the cloud will lift and God will love him. 
 Later the boy says to a white boy that both their clouds will be lifted and God will love them equally when they are free from colour. As a Songs of Innocence, this poem has a more uplifting feel to it.
The Little Black Boy Songs of Innocence