Church Fathers on John 15:7

Having said that they were clean through the word which He had spoken to them, He now taught them that they must do their part.

not they in Him, as He in them; for both are for the profit not of Him, but them. The branches do not confer any advantage upon the vine, but receive their support from it: the vine supplies nourishment to the branches, takes none from them: so that the abiding in Christ, and the having Christ abiding in them, are both for the profit of the disciples, not of Christ; according to what follows, As the branch cannot bear fruit of itself, except it abide in the vine, no more can…

All the fruit of good works proceeds from this root. He who has delivered us by His grace, also carries us onward by his help, so that we bring forth more fruit. Wherefore He repeats, and explains what He has said: I am the vine, you are the branches. He that abides in Me, by believing, obeying, persevering, and I in Him, by enlightening, assisting, giving perseverance, the same, and none other, brings forth much fruit.