The true fruit of an apple tree is not an apple, but more apple trees. Within the fruit is found the seed of the next generation. Christ in us is the seed of the next generation. The difference this seed can leave in the soil of a people group is significant. We all carry within us the seed of future generations of the church. We are to take that seed and plant it in the soil of every people group under the authority of our King.I would add that the ultimate true fruit is glory to God. When an apple tree bears fruit that bears seeds that bear more trees that bear more apples (and so on) that's an amazing organism in action. Who could even think that up much less create it...from scratch...from nothing?
God. Therefore, the ultimate fruit is worship of and glory for God.