Alcuin of York

All the fruit of good works proceeds from this root. He who hath 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, ye are the branches. He that abideth in Me, by believing, obeying, persevering, and I in Him, by enlightening, assisting, giving perseverance, the same, and none other, bringeth forth much fruit.