Following the declaration in the previous verses that the God of the different patriarchs is the same God, he had declared that it was that same God who created the heavens and earth.
That leads to the discussion of the purpose for the creation of this earth by that consistent God. Moroni begins with Adam, and quickly explains the fall, and therefore the necessity of Christ’s atoning sacrifice.
Because Christ has provided the infinite sacrifice and reversed the conditions that required temporal and spiritual death, he is qualified to judge those who have lived on this earth. There will come a time when “he that is filthy shall be filthy still,” and “he that is righteous shall be righteous still.” This life matters to the formation of our eternal character.