8 This is to my Father’s glory, that you bear much fruit, showing yourselves to be my disciples.

Read John 15:8 Using Other Translations

Herein is my Father glorified, that ye bear much fruit; so shall ye be my disciples.
By this my Father is glorified, that you bear much fruit and so prove to be my disciples.
When you produce much fruit, you are my true disciples. This brings great glory to my Father.