Expositor's Bible Commentary Commentary John 15:4

"Abide in me, and I in you. As the branch cannot bear fruit of itself, except it abide in the vine; so neither can ye, except ye abide in me." — John 15:4 (ASV)

Continued production depends on constant union with the source of fruitfulness. Branches that are severed from the parent stock may produce leaves temporarily, but inevitably they will wither because there is no source of life to sustain them; and they will never bear fruit. The effectiveness of believers depends on their receiving the constant flow of life from Christ.