The most likely author of this epistle was Jesus's half-brother, who came to believe after the Resurrection and eventually became the leader of the church. The letter was written to Jewish believers who had become scattered all over the Roman Empire and centers on practical Christian living. It contains numerous references to the Old Testament, and reiterates the Golden Rule (or "the royal law") which first appears in Leviticus: "You shall love your neighbor as yourself." He also asserts that "faith without works is dead."