Jung was not discussing Hell and he was not talking about Heaven. He was instead making an analogy between the mental archetypes of light being opposite darkness; particularly about how those archetypes manifest in both traditional, christian symbolism, as well as theology.
Jung was not a practicing christian in any form, and he was not guiding the reader on how they could go about reaching Heaven in their personal lives. Instead, in the chapter in which this appears, Jung is psycho-analyzing the symbolic and mental archetypes of Christ, within the minds of practicing Protestants. Essentially, Jung is de-constructing the psychological manner in which Christ is received by Christians as the template for their own self identity.
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