How is the slave introduced to the reader in the first stanza?

We are first introduced to the slave in the opening stanza of the poem while he is sleeping, dreaming of the "native land" from which he has been torn. The slave is demarcated not only by the color of his skin —Longfellow does not mention this explicitly, because the reader is able to infer that he is a black man—but by the tools of his forced labor, which he carries even when he is supposedly resting. The "sickle" which he uses to cut down crops and clear fields is in his hand, even as he sleeps, which is an indication that the work of a slave is never done and that he has no real rest. His hair is "matted" and his breast "bare," both indications that the slave is not well looked after, not properly dressed, and not clean because he does not have the time or energy to spend on looking after himself. Instead, all he can do in his snatched moment of peace is dream of the country he has lost, which sets the scene for the "dream" which the poem describes.