In John 15:5, Jesus says “Whoever abides in me and I in him, he it is that bears much fruit, for apart from me you can do nothing.”
What is the “fruit” that Jesus has in view here? Here is a helpful exposition of the text from DA Carson, from his The Gospel according to John:
There has been considerable dispute over the nature of the “fruit” that is envisaged [in this text]: the fruit, we are told, is obedience, or new converts, or love, or Christian character.
These interpretations are reductionistic. The branch’s purpose is to bear much fruit (v. 5), but the next verses show that this fruit is the consequence of prayer in Jesus’ name, and is to the Father’s glory (vv. 7, 8, 16).
This suggests that the “fruit” in the vine imagery represents everything that is the product of effective prayer in Jesus’ name, including obedience to Jesus’ commands (v. 10), experience of Jesus’ joy (v. 11 – as earlier his peace, 14:27), love for one another (v. 12), and witness to the world (vv. 16, 27).
This fruit is nothing less than the outcome of persevering dependence on the vine, driven by faith, embracing all of the believer’s life and the product of his witness.