Two persons love in one another the future good which they aid one another to unfold.

Fuller frames love less as possession or mere feeling than as a mutual, forward-looking commitment to growth. The “future good” suggests that what lovers cherish in each other is not only present charm or virtue but an unrealized potential—capacities, moral strength, intellectual power—that can be brought to fruition. Love, in this view, is collaborative: each person “aids” the other’s unfolding through encouragement, honest recognition, and shared striving. The line reflects a Transcendentalist emphasis on self-culture and becoming, and it implies an ethical standard for relationships: genuine love should enlarge freedom and development rather than restrict it.