Parting is all we know of heaven and all we need to know of hell.

The line contrasts heaven and hell through the human experience of separation. “Parting” is framed as the only concrete “knowledge” we have of heaven—suggesting that whatever heaven is, it is approached through longing, absence, and the hope of reunion. Conversely, parting is also “all we need to know of hell,” implying that the pain of separation (from loved ones, from joy, from life itself) is sufficient to define torment. The aphoristic balance turns an abstract theology into an emotional truth: the deepest metaphysical ideas are felt most sharply in ordinary grief and leave-taking.