He is a piece of property—a marketable commodity

Slavery in the United States is the granting of that power by which one man exercises and enforces a right of property in the body and soul of another. The condition of a slave is simply that of the brute beast. He is a piece of property—a marketable commodity, in the language of the law, to be bought or sold at the will and caprice of the master who claims him to be his property; he is spoken of, thought of, and treated as property. His own good, his conscience, his intellect, his affections, are all set aside by the master. The will and the wishes of the master are the law of the slave.
~ Frederick Douglass (May 12, 1846)