No one in the first century could imagine a world without slavery. Yet it was merely part of an entire social system of obligation in which no one was entirely free. Responsibility was built into their world, whether service to, or benefit from, those above them. These relationships defined them. Modern Christians have lost the sense of responsibility and obedience that is part of a relationship with Jesus. Their obsession with freedom and independence threatens their relationship with Jesus. They see slavery as the opposite of freedom, but the early Christians saw slavery to Jesus as the only real freedom. When Paul said Christians are slaves of Christ, he said it with joy. Moderns, who take that phrase as a metaphor for commitment, miss the point. It is a definition. It is a relationship that defines a person. As Luther said, a Christian is someone who has been ""purchased"" with the blood of Christ, ""that I may be his own, live under him . . . and serve him."" When modern Christians recover the meaning of ""slave of Christ,"" they too can say it with joy.