His heart was as great as the world, but there was no room in it to hold the memory of a wrong.

The line praises a temperament of expansive sympathy paired with an almost radical incapacity for resentment. To say a heart is “as great as the world” suggests an emotional largeness—generosity, openness, and a readiness to include others. The second clause sharpens that largeness into a moral trait: forgiveness so complete that injuries cannot be stored as grievances. In Emersonian terms, this reads like an ideal of self-reliant magnanimity: the noble person refuses to be defined by past slights, and keeps the inner life unencumbered by vindictiveness. The image implies that true greatness is not merely intensity of feeling, but the disciplined freedom to let wrongs pass without becoming one’s identity.