This study is a discussion about Fox's meaning of the "inner light". It argues that Fox's inner light was the celestial Christ who inhabited and divinized the believer. Fox argued for a celestial inhabitation of the believer that was almost corporeal. This helps explain Fox's thaumaturgical powers; the exalted language used among early Quakers, especially toward Fox; and the blasphemy trials and the Nayler incident. These belong at the very centre of early Quakerism, and are the logical result of the core elements of Fox's teaching. His notion of celestial flesh was one of the greatest challenges to Christian orthodoxy to appear in Christian history and it may be compared to Jesus' own challenge to Orthodox Judaism or the appearance of the high heresies of the 2nd and 3rd centuries after Jesus. Early Quakerism, as a result, was the most charismatic sect to appear since the days of the early Church, or at least since the era of Montanism.