This quote is said by Tom to his father, and goes to the very heart of the theme of race, racism and identity that is explored in this brilliant text. What is so interesting about this story is that Tom, as a mulatto, is the product of a relationship between his black mother and the sherrif, his father. However, in the course of the play, the murder for which Tom is accused results in his confrontation with his father and also the confrontation with his own identity. Tom believes that because he is half-white he is better than other blacks. He identifies within himself a spirit and an energy that he believes comes from his white father and that separates him from other blacks.
However, in spite of the possession of this "white man's spirit," Tom finds that his father, because of the way that he treats Tom as just another black man, makes him into a "slave" and crushed this spirit out of him. The quote really reflects the impossible situation that Tom finds himself in. He is not fully black, nor is he fully white. Yet, in spite of his desire to be treated like a white man and his belief that he has characteristics of a white man, the white community, including his father, treat him as if he were just another black man. The quote therefore points to the massive conflict Tom faces as a result of his mixed identity.